diff --git a/STATUS.md b/STATUS.md
new file mode 100644
index 0000000000000..0d7f17d152652
--- /dev/null
+++ b/STATUS.md
@@ -0,0 +1,118 @@
+## Critical Analysis: WP_HTML_Template vs. Ticket #60229 Requirements
+
+I've examined ticket #60229, the current branch implementation, and the test suite. Here's my analysis:
+
+---
+
+### What's Working Well
+
+**1. Core Safety Goal Achieved**
+The implementation delivers on the primary promise: context-aware auto-escaping. The code correctly escapes `&`, `<`, `>`, `"`, `'` in both text and attribute contexts. Tests confirm placeholders can't be injected via replacement values (non-recursive replacement).
+
+**2. Funky Comment Syntax**
+The `</%placeholder>` syntax is a smart choice—it's valid HTML (parsed as a funky comment), can't be nested by construction, and is visually distinctive. The parsing handles whitespace around names correctly.
+
+**3. Nested Templates**
+Template composition (`WP_HTML_Template` as replacement value) works for text context with proper escaping propagation. The rejection of templates in attribute context is the right safety call.
+
+**4. Compile-once Design**
+Lazy compilation with cached edits (`$edits` array) is efficient for template reuse.
+
+**5. Boolean Attribute Support**
+Supply `true` to create a boolean attribute (`disabled="</%d>"` + `true` → `disabled`), or `false`/`null` to remove an attribute entirely. Only works for whole-attribute placeholders—partial placeholders reject boolean values.
+
+---
+
+### What's Missing from the Ticket Requirements
+
+**1. No URL Escaping (Ticket TODO)**
+The ticket explicitly says "does not escape URLs differently than other attributes." The XSS test shows `javascript:alert("xss")` only escapes quotes—no `esc_url()` equivalent. This is a security gap for `href`/`src` attributes.
+
+**2. No Attribute Spread**
+Ticket comment 9 discusses "spread" attributes for making tags placeholders. Not implemented.
+
+**3. Missing Output Format Methods**
+Ticket TODO lists `->final_output_to_browser()`, `->final_output_to_plaintext()`, `->final_output_to_markdown()`, etc. None exist.
+
+**4. Embed Replacement in Tag Processor (Ticket TODO)**
+The ticket wants replacement embedded in the Tag Processor. Current implementation uses a separate class with its own parsing pass.
+
+---
+
+### Overlooked Issues in the Ticket
+
+**1. RAWTEXT/RCDATA Element Handling Is Half-Baked**
+Tests show placeholders inside `<script>`, `<style>` are preserved literally, while `<title>`, `<textarea>` escape them as text. Neither allows actual replacement. The ticket doesn't acknowledge this limitation clearly. If I write a template for a script tag's content, I'd expect placeholders to work.
+
+**2. Table Context Parsing**
+Test explicitly skipped: "IN TABLE templates are not supported yet." HTML parsing rules for tables are complex—implicit elements, foster parenting. The ticket doesn't address this at all. Tables are everywhere in WordPress admin.
+
+**3. No i18n Integration**
+The ticket mentions "translation" as a sigil use case, and gziolo's comment asks about `createInterpolateElement` parity. Zero implementation of translation awareness. For WordPress core, this is a big miss.
+
+**4. Performance Not Benchmarked**
+Normalization runs twice: once in `compile()` for text detection, once in `render()` for final output. For high-frequency template rendering (e.g., list items), this could add up.
+
+**5. Error Handling Philosophy Unclear**
+`render()` returns `false` on errors, but `bind()` uses `_doing_it_wrong()` warnings and still returns a template. Mixed signals—should errors be fatal or recoverable? The test gaps document lists many untested failure cases.
+
+---
+
+### Gaps in Test Coverage (From Test-Gaps.md + My Observations)
+
+**High Priority Missing:**
+
+-   ~~Non-string replacement values (integers, arrays, nulls) → should fail gracefully~~ ✅ Tests exist
+-   ~~Multiple placeholders in single attribute (e.g., `href="</%scheme>://</%host>"`)~~ ✅ Works, tests added
+-   Template immutability verification (`bind()` returns new instance)
+
+**The PRE newline test is skipped** but the behavior matters—WordPress often outputs preformatted code.
+
+**No tests for:**
+
+-   Very long templates/replacements (memory/performance)
+-   Deeply nested templates (stack depth)
+-   Unicode/multibyte characters in placeholder names
+-   SVG/MathML elements
+
+---
+
+### API Design Questions
+
+**1. Why `from()` → `bind()` → `render()` instead of a single call?**
+For reusable templates, the separation makes sense. But most WordPress use cases are one-shot renders. A convenience method like `::render($template, $replacements)` would be more ergonomic.
+
+**2. `render()` Returns `string|false`—Is That Right?**
+Returning `false` on error is classic WordPress, but it means every call site needs error checking. Exceptions or a Result type would be safer, though breaking with WP conventions.
+
+**3. What About Streaming/Chunked Output?**
+For large templates, building the entire string in memory before output is wasteful. No consideration of echo-as-you-go.
+
+---
+
+### What's the Competition Doing That WP Isn't?
+
+-   **Blade/Twig**: Rich conditionals, loops, inheritance. WP_HTML_Template is deliberately minimal.
+-   **htmx/alpine patterns**: Server-side templating with client-side enhancement. No thought given here.
+-   **Lit/React SSR**: Hydration markers. Not applicable, but WP could learn from structured output strategies.
+
+The ticket's philosophy is "prefer trust and safety over features"—valid, but means this won't replace most template use cases. It's targeted at safe HTML generation, not a full templating language.
+
+---
+
+### Summary Table
+
+| Requirement                | Status | Notes                              |
+| -------------------------- | ------ | ---------------------------------- |
+| Context-aware escaping     | ✅     | Works for text and attributes      |
+| Funky comment placeholders | ✅     | Clean implementation               |
+| Nested HTML via Templates  | ✅     | Text context only                  |
+| Boolean attributes         | ✅     | true/false/null for whole-attr     |
+| URL escaping               | ❌     | Only generic escaping              |
+| Attribute spread           | ❌     | Not implemented                    |
+| Output format methods      | ❌     | Not implemented                    |
+| Tag Processor integration  | ❌     | Separate class                     |
+| Table context support      | ❌     | Explicitly unsupported             |
+| i18n integration           | ❌     | Not addressed                      |
+| RAWTEXT/RCDATA replacement | ❌     | Placeholders don't work inside     |
+
diff --git a/src/wp-includes/html-api/class-wp-html-tag-processor.php b/src/wp-includes/html-api/class-wp-html-tag-processor.php
index 69e3e5d2c7557..214e06502260a 100644
--- a/src/wp-includes/html-api/class-wp-html-tag-processor.php
+++ b/src/wp-includes/html-api/class-wp-html-tag-processor.php
@@ -708,7 +708,7 @@ class WP_HTML_Tag_Processor {
 	 * @since 6.2.0
 	 * @var WP_HTML_Attribute_Token[]
 	 */
-	private $attributes = array();
+	protected $attributes = array();
 
 	/**
 	 * Tracks spans of duplicate attributes on a given tag, used for removing
diff --git a/src/wp-includes/html-api/class-wp-html-template.php b/src/wp-includes/html-api/class-wp-html-template.php
new file mode 100644
index 0000000000000..91db36568e3c8
--- /dev/null
+++ b/src/wp-includes/html-api/class-wp-html-template.php
@@ -0,0 +1,451 @@
+<?php
+/**
+ * HTML API: WP_HTML_Template class
+ *
+ * @package WordPress
+ * @subpackage HTML-API
+ * @since 7.0.0
+ */
+
+class WP_HTML_Template {
+	/**
+	 * The template string.
+	 *
+	 * @since 7.0.0
+	 *
+	 * @var string
+	 */
+	private string $template_string;
+
+	/**
+	 * The replacement values for placeholders.
+	 *
+	 * @since 7.0.0
+	 *
+	 * @var array<string, string|self>|null
+	 */
+	private ?array $replacements = null;
+
+	/**
+	 * Unified edit operations list.
+	 *
+	 * Flat array in document order (ascending offsets). Each entry is one of:
+	 *
+	 * Pre-computed replacement (normalizations, escapes):
+	 *   ['start' => int, 'length' => int, 'replacement' => string]
+	 *
+	 * Placeholder reference (render-time lookup):
+	 *   ['start' => int, 'length' => int, 'placeholder' => string, 'context' => 'text'|'attribute']
+	 *
+	 * @since 7.0.0
+	 * @var null|array<array{'start': int, 'length': int, 'placeholder': string, 'context': 'text'|'attribute'}|WP_HTML_Text_Replacement>
+	 */
+	private ?array $edits = null;
+
+	/**
+	 * Placeholder names for O(1) validation.
+	 *
+	 * @since 7.0.0
+	 * @var array<string, true>
+	 */
+	private array $placeholder_names = array();
+
+	/**
+	 * Compiles the template to extract placeholder metadata.
+	 *
+	 * Parses the template once and caches placeholder positions, lengths,
+	 * and contexts. If a placeholder appears in both text and attribute
+	 * contexts, the attribute context takes precedence (more restrictive).
+	 *
+	 * @since 7.0.0
+	 */
+	private function compile(): void {
+		if ( null !== $this->edits ) {
+			return;
+		}
+
+		$this->edits             = array();
+		$this->placeholder_names = array();
+
+		$processor = ( new class( '', WP_HTML_Processor::CONSTRUCTOR_UNLOCK_CODE ) extends WP_HTML_Processor {
+			public function get_html(): string {
+				return $this->html;
+			}
+
+			public function get_bookmark( string $name ) {
+				return $this->bookmarks[ "_{$name}" ] ?? null;
+			}
+
+			public function get_tag_attributes(): array {
+				return $this->attributes;
+			}
+		} )::create_fragment( $this->template_string );
+
+		if ( null === $processor ) {
+			return;
+		}
+
+		while ( $processor->next_token() ) {
+			switch ( $processor->get_token_type() ) {
+				/*
+				 * Track text normalizations to prevent something like
+				 * `a<</%tag-name>u` from becoming `a<i>u` after replacement.
+				 */
+				case '#text':
+					$processor->set_bookmark( 'text' );
+					$mark = $processor->get_bookmark( 'text' );
+					if ( null === $mark ) {
+						break;
+					}
+					$normalized = $processor->serialize_token();
+					if ( 0 !== substr_compare( $processor->get_html(), $normalized, $mark->start, $mark->length ) ) {
+						$this->edits[] = new WP_HTML_Text_Replacement(
+							$mark->start,
+							$mark->length,
+							$normalized,
+						);
+					}
+					break;
+
+				case '#funky-comment':
+					$processor->set_bookmark( 'placeholder' );
+					$mark = $processor->get_bookmark( 'placeholder' );
+					if ( null === $mark ) {
+						break;
+					}
+
+					$start  = $mark->start;
+					$length = $mark->length;
+					$html   = $processor->get_html();
+
+					// Must be at least `</%x>` (5 chars) and start with `</%`
+					if ( $length < 5 || '%' !== $html[ $start + 2 ] ) {
+						break;
+					}
+
+					$placeholder = trim( substr( $html, $start + 3, $length - 4 ), " \t\n\r\f" );
+
+					// Valid placeholders match `/[a-z][a-z0-9_-]*/i` (must start with letter).
+					if (
+						'' === $placeholder ||
+						! ctype_alpha( $placeholder[0] ) ||
+						strlen( $placeholder ) !== strspn( $placeholder, 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-' )
+					) {
+						break;
+					}
+
+					// New: append placeholder edit and register name.
+					$this->edits[]                           = array(
+						'start'       => $start,
+						'length'      => $length,
+						'placeholder' => $placeholder,
+						'context'     => 'text',
+					);
+					$this->placeholder_names[ $placeholder ] = true;
+					break;
+
+				case '#tag':
+					if ( $processor->is_tag_closer() ) {
+						break;
+					}
+
+					$html = $processor->get_html();
+					foreach ( $processor->get_tag_attributes() as $attribute ) {
+						// Boolean attributes cannot contain placeholders.
+						if ( $attribute->is_true ) {
+							continue;
+						}
+						// At least `</%x>` to contain a placeholder.
+						if ( $attribute->value_length < 5 ) {
+							continue;
+						}
+
+						$last_offset = $attribute->value_starts_at;
+						$offset      = $attribute->value_starts_at;
+						$end         = $offset + $attribute->value_length;
+
+						while (
+							1 === preg_match(
+								'#</%[ \\t\\r\\f\\n]*([a-z][a-z0-9_-]*)[ \\t\\r\\f\\n]*>#i',
+								$html,
+								$matches,
+								PREG_OFFSET_CAPTURE,
+								$offset
+							)
+							&& $matches[0][1] < $end
+						) {
+							$placeholder  = $matches[1][0];
+							$match_start  = $matches[0][1];
+							$match_length = strlen( $matches[0][0] );
+
+							// Pre-compute escape for text segment before this placeholder.
+							if ( $match_start > $last_offset ) {
+								$seg_length = $match_start - $last_offset;
+								$original   = substr( $html, $last_offset, $seg_length );
+								$decoded    = WP_HTML_Decoder::decode_attribute( $original );
+								$escaped    = strtr(
+									$decoded,
+									array(
+										'&' => '&amp;',
+										'<' => '&lt;',
+										'>' => '&gt;',
+										"'" => '&apos;',
+										'"' => '&quot;',
+									)
+								);
+								// Only add edit if escaping actually changes the text.
+								if ( $escaped !== $original ) {
+									$this->edits[] = new WP_HTML_Text_Replacement(
+										$last_offset,
+										$seg_length,
+										$escaped,
+									);
+								}
+							}
+
+							// Detect if placeholder is the entire attribute value.
+							$is_whole_attribute = (
+								$match_start === $attribute->value_starts_at &&
+								$match_start + $match_length === $end
+							);
+
+							// Append placeholder edit with attribute metadata.
+							$this->edits[]                           = array(
+								'start'              => $match_start,
+								'length'             => $match_length,
+								'placeholder'        => $placeholder,
+								'context'            => 'attribute',
+								'is_whole_attribute' => $is_whole_attribute,
+								'attr_name'          => $is_whole_attribute ? $attribute->name : null,
+								'attr_start'         => $is_whole_attribute ? $attribute->start : null,
+								'attr_length'        => $is_whole_attribute ? $attribute->length : null,
+							);
+							$this->placeholder_names[ $placeholder ] = true;
+
+							$last_offset = $match_start + $match_length;
+							$offset      = $last_offset;
+						}
+
+						// Pre-compute escape for trailing text segment after last placeholder.
+						if ( $last_offset < $end ) {
+							$seg_length = $end - $last_offset;
+							$original   = substr( $html, $last_offset, $seg_length );
+							$decoded    = WP_HTML_Decoder::decode_attribute( $original );
+							$escaped    = strtr(
+								$decoded,
+								array(
+									'&' => '&amp;',
+									'<' => '&lt;',
+									'>' => '&gt;',
+									"'" => '&apos;',
+									'"' => '&quot;',
+								)
+							);
+							// Only add edit if escaping actually changes the text.
+							if ( $escaped !== $original ) {
+								$this->edits[] = new WP_HTML_Text_Replacement(
+									$last_offset,
+									$seg_length,
+									$escaped,
+								);
+							}
+						}
+					}
+					break;
+			}
+		}
+	}
+
+	private function __construct( string $template_string, ?array $replacements ) {
+		$this->template_string = $template_string;
+		$this->replacements    = $replacements;
+	}
+
+	/**
+	 * Creates a template from a string.
+	 *
+	 * @since 7.0.0
+	 *
+	 * @param string $template The template string with placeholders.
+	 * @return static The template instance.
+	 */
+	public static function from( string $template, ?array $replacements = null ): static {
+		return new static( $template, $replacements );
+	}
+
+	/**
+	 * Returns a new immutable instance with replacements bound.
+	 *
+	 * Triggers compilation if not already done. Validates replacements:
+	 * - Warns if a placeholder has no corresponding replacement
+	 * - Warns if a replacement key has no corresponding placeholder
+	 * - Warns if a template is used in attribute context
+	 *
+	 * @since 7.0.0
+	 *
+	 * @param array $replacements The replacement values.
+	 * @return static A new template instance with the replacements bound.
+	 */
+	public function bind( array $replacements ): static {
+		$this->compile();
+
+		// Check for missing keys (placeholder without replacement).
+		foreach ( $this->placeholder_names as $placeholder => $_ ) {
+			if ( ! array_key_exists( $placeholder, $replacements ) ) {
+				_doing_it_wrong(
+					__METHOD__,
+					sprintf(
+						'Missing replacement for placeholder: %s',
+						$placeholder
+					),
+					'7.0.0'
+				);
+			}
+		}
+
+		// Check for unused keys (replacement without placeholder).
+		foreach ( $replacements as $key => $value ) {
+			if ( ! isset( $this->placeholder_names[ $key ] ) ) {
+				_doing_it_wrong(
+					__METHOD__,
+					sprintf(
+						'Unused replacement key: %s',
+						$key
+					),
+					'7.0.0'
+				);
+			}
+		}
+
+		// Check for templates in attribute context.
+		foreach ( $this->edits as $edit ) {
+			if ( $edit instanceof WP_HTML_Text_Replacement || 'attribute' !== $edit['context'] ) {
+				continue;
+			}
+
+			$placeholder = $edit['placeholder'];
+			$value       = $replacements[ $placeholder ] ?? null;
+
+			if ( $value instanceof self ) {
+				_doing_it_wrong(
+					__METHOD__,
+					sprintf(
+						'Template cannot be used in attribute context: %s',
+						$placeholder
+					),
+					'7.0.0'
+				);
+				break; // Only warn once per placeholder name.
+			}
+		}
+
+		$new                    = new static( $this->template_string, $replacements );
+		$new->edits             = $this->edits;
+		$new->placeholder_names = $this->placeholder_names;
+		return $new;
+	}
+
+	/**
+	 * Renders the template to an HTML string.
+	 *
+	 * Uses pre-compiled placeholder metadata to perform replacements
+	 * without re-parsing. Collects all updates (placeholder replacements,
+	 * text normalizations, attribute text escaping) and applies them
+	 * from end to start using substr_replace() to preserve positions.
+	 *
+	 * Returns false on any error:
+	 * - Missing replacement key (placeholder without corresponding replacement)
+	 * - Unused replacement key (replacement without corresponding placeholder)
+	 * - Template in attribute context
+	 * - HTML processing/normalization failure
+	 *
+	 * @since 7.0.0
+	 *
+	 * @return string|false The rendered HTML, or false on error.
+	 */
+	public function render(): string|false {
+		$this->compile();
+
+		if ( empty( $this->replacements ) ) {
+			// @todo check for missing names.
+			return WP_HTML_Processor::normalize( $this->template_string ) ?? $this->template_string;
+		}
+
+		$escape_map = array(
+			'&' => '&amp;',
+			'<' => '&lt;',
+			'>' => '&gt;',
+			"'" => '&apos;',
+			'"' => '&quot;',
+		);
+
+		$processor = ( new class( $this->template_string ) extends WP_HTML_Tag_Processor {
+			public function push_update( WP_HTML_Text_Replacement $update ) {
+				$this->lexical_updates[] = $update;
+			}
+		} );
+
+		$used_keys = array();
+		foreach ( $this->edits as $edit ) {
+			if ( $edit instanceof WP_HTML_Text_Replacement ) {
+				$processor->push_update( $edit );
+			} else {
+				// Placeholder: look up replacement value.
+				$placeholder = $edit['placeholder'];
+				$value       = $this->replacements[ $placeholder ] ?? null;
+
+				if ( $value instanceof self ) {
+					if ( 'attribute' === $edit['context'] ) {
+						// @todo doing it wrong.
+						return false;
+					}
+
+					$rendered = $value->render();
+					if ( false === $rendered ) {
+						return false;
+					}
+
+					$processor->push_update(
+						new WP_HTML_Text_Replacement( $edit['start'], $edit['length'], $rendered ),
+					);
+				} elseif ( is_string( $value ) ) {
+					$escaped = strtr( $value, $escape_map );
+					$processor->push_update(
+						new WP_HTML_Text_Replacement( $edit['start'], $edit['length'], $escaped ),
+					);
+				} elseif ( true === $value ) {
+					// Boolean true: convert to boolean attribute (remove value, keep name).
+					if ( empty( $edit['is_whole_attribute'] ) ) {
+						return false;
+					}
+					$processor->push_update(
+						new WP_HTML_Text_Replacement( $edit['attr_start'], $edit['attr_length'], $edit['attr_name'] ),
+					);
+				} elseif ( false === $value || null === $value ) {
+					// Boolean false or null: remove entire attribute.
+					if ( empty( $edit['is_whole_attribute'] ) ) {
+						return false;
+					}
+					$processor->push_update(
+						new WP_HTML_Text_Replacement( $edit['attr_start'], $edit['attr_length'], '' ),
+					);
+				} else {
+					// @todo doing it wrong.
+					return false;
+				}
+				$used_keys[ $placeholder ] = true;
+			}
+		}
+
+		// Return false if any replacement key was not used.
+		if ( count( $used_keys ) !== count( $this->replacements ) ) {
+			return false;
+		}
+
+		/*
+		 * @todo ideally, just call `$processor->serialize()`.
+		 * @todo doing it wrong?
+		 */
+		return WP_HTML_Processor::normalize( $processor->get_updated_html() ) ?? false;
+	}
+}
diff --git a/src/wp-settings.php b/src/wp-settings.php
index 60c220100f539..b80167116f541 100644
--- a/src/wp-settings.php
+++ b/src/wp-settings.php
@@ -276,6 +276,7 @@
 require ABSPATH . WPINC . '/html-api/class-wp-html-stack-event.php';
 require ABSPATH . WPINC . '/html-api/class-wp-html-processor-state.php';
 require ABSPATH . WPINC . '/html-api/class-wp-html-processor.php';
+require ABSPATH . WPINC . '/html-api/class-wp-html-template.php';
 require ABSPATH . WPINC . '/class-wp-block-processor.php';
 require ABSPATH . WPINC . '/class-wp-http.php';
 require ABSPATH . WPINC . '/class-wp-http-streams.php';
diff --git a/templating-examples.php b/templating-examples.php
new file mode 100644
index 0000000000000..2c9e4e80b83f3
--- /dev/null
+++ b/templating-examples.php
@@ -0,0 +1,205 @@
+<?php
+/**
+ * HTML Templating API - Usage Examples
+ *
+ * This file documents real patterns from WordPress core that could benefit
+ * from the WP_HTML_Template API. These are reference examples for API design.
+ *
+ * @see Trac #60229 - HTML API: Introduce HTML Templating
+ */
+
+die( 'demonstration - not for execution' );
+
+/**
+ * =============================================================================
+ * PATTERN 1: Translation functions with embedded HTML
+ * =============================================================================
+ *
+ * These patterns have HTML tags directly in the translatable string.
+ * Translators see the HTML, which is problematic.
+ */
+
+// src/wp-includes/functions.php:1620
+// Simple HTML tag in translation
+wp_die( __( '<strong>Error:</strong> This is not a valid feed template.' ), '', array( 'response' => 404 ) );
+
+// src/wp-includes/functions.php:1844-1845
+// Link with placeholder inside translation
+$wpdb->error = sprintf(
+	/* translators: %s: Database repair URL. */
+	__( 'One or more database tables are unavailable. The database may need to be <a href="%s">repaired</a>.' ),
+	'maint/repair.php?referrer=is_blog_installed'
+);
+
+// src/wp-admin/edit-form-advanced.php:185
+// HTML wrapper injected as sprintf parameter
+$messages['post'][9] = sprintf( __( 'Post scheduled for: %s.' ), '<strong>' . $scheduled_date . '</strong>' ) . $scheduled_post_link_html;
+
+// src/wp-admin/revision.php:145-147
+// Multiple strong tags for emphasis in help text
+$revisions_overview .= '<ul><li>' . __( 'To navigate between revisions, <strong>drag the slider handle left or right</strong> or <strong>use the Previous or Next buttons</strong>.' ) . '</li>';
+$revisions_overview .= '<li>' . __( 'Compare two different revisions by <strong>selecting the &#8220;Compare any two revisions&#8221; box</strong> to the side.' ) . '</li>';
+$revisions_overview .= '<li>' . __( 'To restore a revision, <strong>click Restore This Revision</strong>.' ) . '</li></ul>';
+
+// src/wp-includes/theme.php:978-979
+// Context translation (_x) with HTML error prefix
+return new WP_Error(
+	'theme_wp_php_incompatible',
+	sprintf(
+		/* translators: %s: Theme name. */
+		_x( '<strong>Error:</strong> Current WordPress and PHP versions do not meet minimum requirements for %s.', 'theme' ),
+		$theme->display( 'Name' )
+	)
+);
+
+// src/wp-includes/widgets/class-wp-widget-text.php:542
+// Complex: _e() with embedded link and HTML entities
+_e( 'Did you know there is a &#8220;Custom HTML&#8221; widget now? You can find it by pressing the &#8220;<a class="add-widget" href="#">Add a Widget</a>&#8221; button and searching for &#8220;HTML&#8221;. Check it out to add some custom code to your site!' );
+
+// src/wp-includes/blocks/comments-title.php:29
+// HTML entities (curly quotes) in translation
+$post_title = sprintf( __( '&#8220;%s&#8221;' ), get_the_title() );
+
+// src/wp-includes/blocks/latest-posts.php:164-166
+// Complex nested HTML with multiple escaped placeholders
+$trimmed_excerpt .= sprintf(
+	/* translators: 1: A URL to a post, 2: Hidden accessibility text: Post title */
+	__( '… <a class="wp-block-latest-posts__read-more" href="%1$s" rel="noopener noreferrer">Read more<span class="screen-reader-text">: %2$s</span></a>' ),
+	esc_url( $post_link ),
+	esc_html( $title )
+);
+
+// src/wp-admin/includes/class-plugin-upgrader.php:60
+// HTML span wrapping another placeholder (double sprintf)
+$this->strings['downloading_package'] = sprintf( __( 'Downloading update from %s&#8230;' ), '<span class="code pre">%s</span>' );
+
+// src/wp-admin/includes/privacy-tools.php:404
+// Code tag wrapping technical reference
+sprintf( __( 'The %s post meta must be an array.' ), '<code>_export_data_grouped</code>' );
+
+// src/wp-admin/widgets.php:24
+// Full paragraph with embedded documentation link
+wp_die( __( 'The theme you are currently using is not widget-aware, meaning that it has no sidebars that you are able to change. For information on making your theme widget-aware, please <a href="https://developer.wordpress.org/themes/functionality/widgets/">follow these instructions</a>.' ) );
+
+// src/wp-admin/revision.php:158
+// Link in translation without placeholders
+$revisions_sidebar .= '<p>' . __( '<a href="https://wordpress.org/documentation/article/revisions/">Revisions Management</a>' ) . '</p>';
+
+
+/**
+ * =============================================================================
+ * PATTERN 2: sprintf with manual escaping (non-translation)
+ * =============================================================================
+ *
+ * These patterns require developers to choose the correct escape function
+ * for each context (esc_url, esc_attr, esc_html).
+ */
+
+// src/wp-includes/blocks/post-title.php:41
+// Link with multiple escaped attributes
+$rel   = ! empty( $attributes['rel'] ) ? 'rel="' . esc_attr( $attributes['rel'] ) . '"' : '';
+$title = sprintf(
+	'<a href="%1$s" target="%2$s" %3$s>%4$s</a>',
+	esc_url( get_the_permalink( $block->context['postId'] ) ),
+	esc_attr( $attributes['linkTarget'] ),
+	$rel,    // Note: $rel already has esc_attr inside
+	$title   // Note: $title escaping unclear
+);
+
+// src/wp-includes/blocks/avatar.php:68
+// Similar link pattern for avatar
+$avatar_block = sprintf(
+	'<a href="%1$s" target="%2$s" %3$s class="wp-block-avatar__link">%4$s</a>',
+	esc_url( get_author_posts_url( $author_id ) ),
+	esc_attr( $attributes['linkTarget'] ),
+	$label,        // aria-label attribute, already escaped
+	$avatar_block  // Inner HTML
+);
+
+// src/wp-includes/formatting.php:3476
+// Image tag with esc_url and esc_attr
+return sprintf(
+	'<img src="%s" alt="%s" class="wp-smiley" style="height: 1em; max-height: 1em;" />',
+	esc_url( $src_url ),
+	esc_attr( $smiley )
+);
+
+// src/wp-includes/class-wp-styles.php:204-211
+// Link tag with nested sprintf for conditional attribute
+$tag = sprintf(
+	"<link rel='%s' id='%s-css'%s href='%s' media='%s' />\n",
+	$rel,                                                    // Not escaped
+	esc_attr( $handle ),
+	$title ? sprintf( " title='%s'", esc_attr( $title ) ) : '',
+	$href,                                                   // Not escaped
+	esc_attr( $media )
+);
+
+
+/**
+ * =============================================================================
+ * PATTERN 3: Building aria-label attributes
+ * =============================================================================
+ */
+
+// src/wp-includes/blocks/avatar.php:65
+// Aria label with translation and escaping
+$label = 'aria-label="' . esc_attr( sprintf( __( '(%s author archive, opens in a new tab)' ), $author_name ) ) . '"';
+
+
+/**
+ * =============================================================================
+ * POTENTIAL TEMPLATING ALTERNATIVES
+ * =============================================================================
+ *
+ * How these patterns could look with WP_HTML_Template.
+ */
+
+/*
+ * OPTION A: Template wraps translation (structure in code, text translated)
+ *
+ * HTML structure stays in PHP code, only text content is translated.
+ */
+
+// Instead of: __( '<strong>Error:</strong> This is not a valid feed template.' )
+WP_HTML_Template::render(
+	'<strong></%label></strong> </%message>',
+	array(
+		'label'   => __( 'Error:' ),
+		'message' => __( 'This is not a valid feed template.' ),
+	)
+);
+
+// Instead of: sprintf( __( 'Post scheduled for: %s.' ), '<strong>' . $date . '</strong>' )
+WP_HTML_Template::render(
+	__( 'Post scheduled for: %s.', 'template-placeholder' ), // Special handling?
+	// Or:
+	'</%before><strong></%date></strong></%after>',
+	array(
+		'before' => __( 'Post scheduled for: ' ),
+		'date'   => $scheduled_date,
+		'after'  => '',
+	)
+);
+
+/*
+ * OPTION B: Translation contains template placeholders
+ *
+ * Translated string includes the </%name> syntax directly.
+ * This is closer to how WordPress translations work today.
+ */
+
+// Instead of: sprintf( __( '... <a href="%s">repaired</a>.' ), $url )
+WP_HTML_Template::render(
+	__( 'One or more database tables are unavailable. The database may need to be <a href="</%url>">repaired</a>.' ),
+	array( 'url' => 'maint/repair.php?referrer=is_blog_installed' )
+);
+
+// Instead of: sprintf( __( '... href="%1$s" ... %2$s ...' ), esc_url($url), esc_html($title) )
+WP_HTML_Template::render(
+	__( '… <a class="wp-block-latest-posts__read-more" href="</%url>" rel="noopener noreferrer">Read more<span class="screen-reader-text">: </%title></span></a>' ),
+	array(
+		'url'   => $post_link,   // Auto-escaped as URL in href context
+		'title' => $title,       // Auto-escaped as text in text context
+	)
+);
diff --git a/tests/phpunit/tests/html-api/wpHtmlTemplate.php b/tests/phpunit/tests/html-api/wpHtmlTemplate.php
new file mode 100644
index 0000000000000..c27dfb3c81dd5
--- /dev/null
+++ b/tests/phpunit/tests/html-api/wpHtmlTemplate.php
@@ -0,0 +1,1131 @@
+<?php
+/**
+ * Unit tests covering WP_HTML_Template functionality.
+ *
+ * @package WordPress
+ * @subpackage HTML-API
+ *
+ * @since 7.0.0
+ *
+ * @group html-api
+ * @group TBD
+ *
+ * @coversDefaultClass WP_HTML_Template
+ */
+
+use WP_HTML_Template as T;
+
+class Tests_HtmlApi_WpHtmlTemplate extends WP_UnitTestCase {
+	/**
+	 * Verifies that replacement text adjacent to angle brackets is escaped.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_escapes_text_adjacent_to_angle_brackets() {
+		$template_string = 'a<</%tag-name>>s';
+		$replacements    = array( 'tag-name' => 'i' );
+		$result          = T::from( $template_string )->bind( $replacements )->render();
+
+		$expected = 'a&lt;i&gt;s';
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies that only the first of duplicate attributes is replaced.
+	 *
+	 * Note: Duplicate attributes are stripped per HTML spec, so placeholders
+	 * in duplicate attributes are ignored. Providing a replacement for such
+	 * placeholders would be an unused key error.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_replaces_only_in_first_duplicate_attribute() {
+		$template_string = '<meta a="</%replace></%replace-2>" a="</% no-replace >">';
+		$replacements    = array(
+			'replace'   => 'O',
+			'replace-2' => 'K',
+		);
+
+		$result = T::from( $template_string )->bind( $replacements )->render();
+
+		$expected = '<meta a="OK">';
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies that attribute replacement is not recursive.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_attribute_replacement_is_not_recursive() {
+		$template_string = '<div a="</%replace>"></%replace></div>';
+		$replacements    = array(
+			'replace' => '</%replace>',
+		);
+
+		$result = T::from( $template_string )->bind( $replacements )->render();
+
+		$expected = '<div a="&lt;/%replace&gt;">&lt;/%replace&gt;</div>';
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies that placeholder names allow surrounding whitespace.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_placeholder_names_allow_surrounding_whitespace() {
+		$template_string = "<meta name='</%\tn\n>' content='</% c\r\f>'>";
+		$replacements    = array(
+			'n' => 'the name',
+			'c' => 'the "content" & whatever else',
+		);
+
+		$result = T::from( $template_string )->bind( $replacements )->render();
+
+		$expected =
+			<<<'HTML'
+			<meta name="the name" content="the &quot;content&quot; &amp; whatever else">
+			HTML;
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies that ampersands are escaped to prevent character reference injection.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_escapes_ampersand_to_prevent_character_reference_injection() {
+		$template_string = '<meta name="&</% placeholder >;">';
+		$replacements    = array( 'placeholder' => 'not' );
+		$result          = T::from( $template_string )->bind( $replacements )->render();
+
+		$expected =
+			<<<'HTML'
+			<meta name="&amp;not;">
+			HTML;
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies that nested templates are rejected in attribute values.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 *
+	 * @expectedIncorrectUsage WP_HTML_Template::bind
+	 */
+	public function test_rejects_nested_template_in_attribute_value() {
+		$template_string = '<meta name="not-allowed" description="</%html>">';
+		$replacements    = array(
+			'html' => T::from( '<strong>This is not allowed!</strong>' ),
+		);
+		$this->assertFalse( T::from( $template_string )->bind( $replacements )->render() );
+	}
+
+	/**
+	 * @dataProvider data_template
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_template( string $template_string, array $replacements, string $expected ) {
+		$result = T::from( $template_string )->bind( $replacements )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	public static function data_template() {
+		return array(
+			'basic template (no placeholders)'   => array(
+				'<p>Hi!</p>',
+				array(),
+				'<p>Hi!</p>',
+			),
+
+			'basic text replacement'             => array(
+				'<p>Hello, </%name>!</p>',
+				array( 'name' => 'World' ),
+				'<p>Hello, World!</p>',
+			),
+
+			'escapes special characters in text' => array(
+				'<p>Hello, </%placeholder>!</p>',
+				array( 'placeholder' => 'Alice & Bob' ),
+				'<p>Hello, Alice &amp; Bob!</p>',
+			),
+
+			'escapes angle brackets in text'     => array(
+				'<p>Hello, </%name>!</p>',
+				array( 'name' => '<little-bobby-tags>' ),
+				'<p>Hello, &lt;little-bobby-tags&gt;!</p>',
+			),
+
+			'repeated placeholders'              => array(
+				'<p></%a>, </% a >, </%name>, & </%name>!</p>',
+				array(
+					'a'    => 'Alice',
+					'name' => 'Bob',
+				),
+				'<p>Alice, Alice, Bob, &amp; Bob!</p>',
+			),
+
+			'nested template replacement'        => array(
+				'<p>Hello, </%html>',
+				array( 'html' => WP_HTML_Template::from( '<i>Alice</i> & <i>Bob</i>' ) ),
+				'<p>Hello, <i>Alice</i> &amp; <i>Bob</i></p>',
+			),
+
+			'replaces attribute values'          => array(
+				'<meta name="</%n>" content="</%c>">',
+				array(
+					'n' => 'the name',
+					'c' => 'the content',
+				),
+				'<meta name="the name" content="the content">',
+			),
+
+			'escapes attribute values'           => array(
+				'<meta content="</%c>">',
+				array(
+					'c' => 'the "content" & whatever else',
+				),
+				'<meta content="the &quot;content&quot; &amp; whatever else">',
+			),
+		);
+	}
+
+	/**
+	 * Test real-world patterns from WordPress core.
+	 *
+	 * @dataProvider data_real_world_examples
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_real_world_examples( string $template_string, array $replacements, string $expected ) {
+		$result = WP_HTML_Template::from( $template_string )->bind( $replacements )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Data provider with real-world patterns from WordPress core.
+	 *
+	 * Each test case is based on actual code patterns found in WordPress core
+	 * that could benefit from the WP_HTML_Template API.
+	 *
+	 * @return array[]
+	 */
+	public static function data_real_world_examples() {
+		/*
+		 * Group 1: Simple sprintf patterns with manual escaping.
+		 *
+		 * These patterns currently require developers to manually choose
+		 * the correct escape function (esc_url, esc_attr, esc_html).
+		 */
+
+		// src/wp-includes/formatting.php:3476 - Smiley image
+		yield 'formatting.php:3476 - smiley image tag' => array(
+			<<<'HTML'
+			<img src="</%src>" alt="</%alt>" class="wp-smiley" style="height: 1em; max-height: 1em;" />
+			HTML,
+			array(
+				'src' => 'https://example.com/smilies/:).png',
+				'alt' => ':)',
+			),
+			<<<'HTML'
+			<img src="https://example.com/smilies/:).png" alt=":)" class="wp-smiley" style="height: 1em; max-height: 1em;" />
+			HTML,
+		);
+
+		// src/wp-includes/blocks/post-title.php:41 - Post title link
+		yield 'blocks/post-title.php:41 - post title link' => array(
+			'<a href="</%url>" target="</%target>"></%title></a>',
+			array(
+				'url'    => 'https://example.com/hello-world/',
+				'target' => '_blank',
+				'title'  => 'Hello World',
+			),
+			'<a href="https://example.com/hello-world/" target="_blank">Hello World</a>',
+		);
+
+		// Same pattern with escaping needed
+		yield 'blocks/post-title.php:41 - post title link with special chars' => array(
+			"<a href='</%url>' target='</%target>'>\n</%title>\n</a>",
+			array(
+				'url'    => 'https://example.com/hello-world/?foo=1&bar=2',
+				'target' => '_blank',
+				'title'  => WP_HTML_Template::from( '\'<i></%italic></i>\' & <b>"</%bold>"</b>' )
+					->bind(
+						array(
+							'italic' => 'This',
+							'bold'   => 'That',
+						)
+					),
+			),
+			<<<'HTML'
+			<a href="https://example.com/hello-world/?foo=1&amp;bar=2" target="_blank">
+			&apos;<i>This</i>' &amp; <b>&quot;That"</b>
+			</a>
+			HTML,
+		);
+
+		/*
+		 * Group 2: Translation patterns with embedded HTML.
+		 *
+		 * These patterns have HTML directly in translatable strings.
+		 */
+
+		// src/wp-includes/functions.php:1620 - Error message (static, no placeholders)
+		yield 'functions.php:1620 - static error message' => array(
+			'<strong>Error:</strong> This is not a valid feed template.',
+			array(),
+			'<strong>Error:</strong> This is not a valid feed template.',
+		);
+
+		// src/wp-includes/functions.php:1844-1845 - Database repair link
+		yield 'functions.php:1844 - database repair link' => array(
+			<<<'HTML'
+			One or more database tables are unavailable. The database may need to be <a href="</%url>">repaired</a>.
+			HTML,
+			array(
+				'url' => 'maint/repair.php?referrer=is_blog_installed',
+			),
+			<<<'HTML'
+			One or more database tables are unavailable. The database may need to be <a href="maint/repair.php?referrer=is_blog_installed">repaired</a>.
+			HTML,
+		);
+
+		// src/wp-admin/edit-form-advanced.php:185 - Scheduled post date
+		yield 'edit-form-advanced.php:185 - scheduled post date' => array(
+			'Post scheduled for: <strong></%date></strong>.',
+			array(
+				'date' => 'March 15, 2025 at 10:30 am',
+			),
+			'Post scheduled for: <strong>March 15, 2025 at 10:30 am</strong>.',
+		);
+
+		// src/wp-includes/blocks/latest-posts.php:164-166 - Read more link with nested elements
+		yield 'blocks/latest-posts.php:164 - read more link with screen reader text' => array(
+			<<<'HTML'
+			… <a class="wp-block-latest-posts__read-more" href="</%url>" rel="noopener noreferrer">Read more<span class="screen-reader-text">: </%title></span></a>
+			HTML,
+			array(
+				'url'   => 'https://example.com/my-post/',
+				'title' => 'My Amazing Post',
+			),
+			<<<'HTML'
+			… <a class="wp-block-latest-posts__read-more" href="https://example.com/my-post/" rel="noopener noreferrer">Read more<span class="screen-reader-text">: My Amazing Post</span></a>
+			HTML,
+		);
+
+		// Same pattern with escaping needed
+		yield 'blocks/latest-posts.php:164 - read more with XSS attempt' => array(
+			<<<'HTML'
+			… <a class="wp-block-latest-posts__read-more" href="</%url>" rel="noopener noreferrer">Read more<span class="screen-reader-text">: </%title></span></a>
+			HTML,
+			array(
+				'url'   => 'javascript:alert("xss")',
+				'title' => '<script>alert("xss")</script>',
+			),
+			<<<'HTML'
+			… <a class="wp-block-latest-posts__read-more" href="javascript:alert(&quot;xss&quot;)" rel="noopener noreferrer">Read more<span class="screen-reader-text">: &lt;script&gt;alert("xss")&lt;/script&gt;</span></a>
+			HTML,
+		);
+
+		// src/wp-includes/theme.php:978-979 - Theme error with name
+		yield 'theme.php:978 - theme error message' => array(
+			<<<'HTML'
+			<strong>Error:</strong> Current WordPress and PHP versions do not meet minimum requirements for </%theme_name>.
+			HTML,
+			array(
+				'theme_name' => 'Twenty Twenty-Five',
+			),
+			<<<'HTML'
+			<strong>Error:</strong> Current WordPress and PHP versions do not meet minimum requirements for Twenty Twenty-Five.
+			HTML,
+		);
+
+		// src/wp-admin/includes/privacy-tools.php:404 - Code tag in error
+		yield 'privacy-tools.php:404 - code in error message' => array(
+			'The <code></%meta_key></code> post meta must be an array.',
+			array(
+				'meta_key' => '_export_data_grouped',
+			),
+			'The <code>_export_data_grouped</code> post meta must be an array.',
+		);
+
+		/*
+		 * Group 3: Edge cases.
+		 */
+
+		// Placeholder reuse (same placeholder multiple times)
+		yield 'placeholder reuse' => array(
+			'<label for="</%id>">Name:</label> <input id="</%id>" name="</%id>" type="text" />',
+			array(
+				'id' => 'user_name',
+			),
+			'<label for="user_name">Name:</label> <input id="user_name" name="user_name" type="text" />',
+		);
+
+		// Named placeholders
+		yield 'named placeholders' => array(
+			'<a href="</%postUrl>"></%postTitle></a> by <a href="</%authorUrl>"></%authorName></a>',
+			array(
+				'postUrl'    => 'https://example.com/post/',
+				'postTitle'  => 'Post Title',
+				'authorUrl'  => 'https://example.com/author/',
+				'authorName' => 'Author Name',
+			),
+			'<a href="https://example.com/post/">Post Title</a> by <a href="https://example.com/author/">Author Name</a>',
+		);
+
+		// Nested template (pre-escaped HTML)
+		yield 'nested template for complex structure' => array(
+			'<div class="error"></%icon> </%message></div>',
+			array(
+				'icon'    => WP_HTML_Template::from( '<span class="dashicons dashicons-warning"></span>' ),
+				'message' => 'Something went wrong.',
+			),
+			'<div class="error"><span class="dashicons dashicons-warning"></span> Something went wrong.</div>',
+		);
+
+		// Empty replacement
+		yield 'empty replacement value' => array(
+			'<p>Hello</%suffix></p>',
+			array(
+				'suffix' => '',
+			),
+			'<p>Hello</p>',
+		);
+
+		// HTML entities in template (should be preserved)
+		yield 'HTML entities in template' => array(
+			'<p>&#8220;</%quote>&#8221;</p>',
+			array(
+				'quote' => 'Hello World',
+			),
+			'<p>&#8220;Hello World&#8221;</p>',
+		);
+
+		// Multiple attributes on same element
+		yield 'multiple attributes on element' => array(
+			'<input type="</%type>" name="</%name>" value="</%value>" placeholder="</%placeholder>" />',
+			array(
+				'type'        => 'text',
+				'name'        => 'user_email',
+				'value'       => 'test@example.com',
+				'placeholder' => 'Enter your email',
+			),
+			'<input type="text" name="user_email" value="test@example.com" placeholder="Enter your email" />',
+		);
+
+		// Attribute value with quotes and special characters
+		yield 'attribute with quotes and ampersands' => array(
+			'<a href="</%url>" title="</%title>">Link</a>',
+			array(
+				'url'   => 'https://example.com/?a=1&b=2',
+				'title' => <<<'TEXT'
+				Click "here" for Tom & Jerry
+				TEXT,
+			),
+			<<<'HTML'
+			<a href="https://example.com/?a=1&amp;b=2" title="Click &quot;here&quot; for Tom &amp; Jerry">Link</a>
+			HTML,
+		);
+
+		// Self-closing void element
+		yield 'self-closing meta tag' => array(
+			'<meta name="</%name>" content="</%content>">',
+			array(
+				'name'    => 'description',
+				'content' => <<<'TEXT'
+				A page about "cats" & dogs
+				TEXT,
+			),
+			<<<'HTML'
+			<meta name="description" content="A page about &quot;cats&quot; &amp; dogs">
+			HTML,
+		);
+
+		// src/wp-includes/blocks/avatar.php:68 - Complex link with aria-label
+		yield 'blocks/avatar.php:68 - avatar link' => array(
+			<<<'HTML'
+			<a href="</%url>" target="</%target>" aria-label="</%aria_label>" class="wp-block-avatar__link"></%inner></a>
+			HTML,
+			array(
+				'url'        => 'https://example.com/author/johndoe/',
+				'target'     => '_blank',
+				'aria_label' => '(John Doe author archive, opens in a new tab)',
+				'inner'      => WP_HTML_Template::from( '<img src="https://example.com/avatar.jpg" alt="John Doe" />' ),
+			),
+			<<<'HTML'
+			<a href="https://example.com/author/johndoe/" target="_blank" aria-label="(John Doe author archive, opens in a new tab)" class="wp-block-avatar__link"><img src="https://example.com/avatar.jpg" alt="John Doe" /></a>
+			HTML,
+		);
+	}
+
+	/**
+	 * Verifies nested templates work correctly in a definition list.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_nested_templates_in_definition_list() {
+		$row_template = WP_HTML_Template::from( "<dt></%term></dt>\n<dd></%definition></dd>" );
+
+		$row_replacements = array();
+		for ( $i = 1; $i <= 3; $i++ ) {
+			$row_replacements[ "row-{$i}" ] = $row_template->bind(
+				array(
+					'term'       => "Term \"{$i}\"",
+					'definition' => WP_HTML_Template::from( '<abbr title="</%expansion>">IYKYK</abbr>: </%i>' )
+						->bind(
+							array(
+								'i'         => (string) $i,
+								'expansion' => '"If You Know You Know"',
+							)
+						),
+				)
+			);
+		}
+
+		$result = WP_HTML_Template::from(
+			<<<'HTML'
+			<dl>
+			</%row-1>
+			</%row-2>
+			</%row-3>
+			</dl>
+			HTML
+		)->bind( $row_replacements )->render();
+
+		$expected =
+			<<<'HTML'
+			<dl>
+			<dt>Term &quot;1&quot;</dt>
+			<dd><abbr title="&quot;If You Know You Know&quot;">IYKYK</abbr>: 1</dd>
+			<dt>Term &quot;2&quot;</dt>
+			<dd><abbr title="&quot;If You Know You Know&quot;">IYKYK</abbr>: 2</dd>
+			<dt>Term &quot;3&quot;</dt>
+			<dd><abbr title="&quot;If You Know You Know&quot;">IYKYK</abbr>: 3</dd>
+			</dl>
+			HTML;
+
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies table templates are not yet supported.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_table_templates_not_yet_supported() {
+		$this->markTestSkipped( 'IN TABLE templates are not supported yet.' );
+		$header_tpl = WP_HTML_Template::from( '<tr><th></% ID ><th></% name ><th></% value ><th></% link >' )
+			->bind(
+				array(
+					'ID'    => 'ID',
+					'name'  => 'Name',
+					'value' => 'Value',
+					'link'  => 'Link',
+				)
+			);
+		$row_tpl    = WP_HTML_Template::from( '<tr><td></% ID ><td></% name ><td></% value ><td></% link >' );
+
+		$row_gen = ( function () {
+			static $i = 1;
+			yield array(
+				'ID'    => $i,
+				'name'  => 'Name {$i}',
+				'value' => WP_HTML_Template::from( 'Value <b>{$i}</b>' )->bind( array( 'i' => $i ) ),
+				'link'  => WP_HTML_Template::from( '<a href="</%url>"></%link-name></a>' )
+					->bind(
+						array(
+							'url'       => '/example/1',
+							'link-name' => 'Click here',
+						)
+					),
+			);
+		} )();
+
+		$result = WP_HTML_Template::from(
+			<<<'HTML'
+			<table>
+			<thead></%header>
+			<tbody>
+			</%row-1>
+			</%row-2>
+			</%row-3>
+			HTML
+		)->bind(
+			array(
+				'header' => $header_tpl,
+				'row-1'  => $row_tpl->bind( $row_gen->next() ),
+				'row-2'  => $row_tpl->bind( $row_gen->next() ),
+				'row-3'  => $row_tpl->bind( $row_gen->next() ),
+			)
+		)->render();
+
+		$expected =
+			<<<'HTML'
+			HTML;
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	/**
+	 * Verifies that attributes are replaced in atomic elements (SCRIPT, STYLE, TITLE).
+	 *
+	 * These elements have special parsing rules that skip their content,
+	 * but attributes should still be processed normally.
+	 *
+	 * @ticket 60229
+	 *
+	 * @dataProvider data_atomic_element_attributes
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_atomic_element_attributes_are_replaced( string $template_string, array $replacements, string $expected ) {
+		$result = T::from( $template_string )->bind( $replacements )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	public static function data_atomic_element_attributes() {
+		return array(
+			'SCRIPT element attributes'   => array(
+				'<script src="</%src>">console.log("hi")</script>',
+				array( 'src' => '/js/app.js' ),
+				'<script src="/js/app.js">console.log("hi")</script>',
+			),
+
+			'STYLE element attributes'    => array(
+				'<style media="</%media>">.foo { color: red; }</style>',
+				array( 'media' => 'screen' ),
+				'<style media="screen">.foo { color: red; }</style>',
+			),
+
+			'TITLE element attributes'    => array(
+				'<title lang="</%lang>">Page Title</title>',
+				array( 'lang' => 'en' ),
+				'<title lang="en">Page Title</title>',
+			),
+
+			'TEXTAREA element attributes' => array(
+				'<textarea name="</%name>">Some content</textarea>',
+				array( 'name' => 'my-textarea' ),
+				'<textarea name="my-textarea">Some content</textarea>',
+			),
+		);
+	}
+
+	/**
+	 * Verifies content placeholder behavior in elements with special parsing.
+	 *
+	 * - RAWTEXT elements (SCRIPT, STYLE): Content is skipped, placeholders preserved literally.
+	 * - RCDATA elements (TITLE, TEXTAREA): Content is processed but placeholders are not
+	 *   recognized - they're treated as literal text and HTML-escaped.
+	 *
+	 * With strict validation, providing a replacement for a placeholder that won't be
+	 * processed (inside SCRIPT/STYLE/TITLE/TEXTAREA) is an unused key error.
+	 *
+	 * @ticket 60229
+	 *
+	 * @dataProvider data_atomic_element_content_placeholders
+	 *
+	 * @todo Implement correct handling of atomic elements.
+	 *
+	 * @covers ::from
+	 * @covers ::render
+	 */
+	public function test_special_element_content_placeholder_behavior( string $template_string, string $expected ) {
+		$result = T::from( $template_string )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	public static function data_atomic_element_content_placeholders() {
+		return array(
+			// RAWTEXT elements (SCRIPT, STYLE): Content is truly skipped, placeholders preserved literally.
+			'SCRIPT content placeholder preserved' => array(
+				'<script>var x = "</%name>";</script>',
+				'<script>var x = "</%name>";</script>',
+			),
+
+			'STYLE content placeholder preserved'  => array(
+				'<style>.foo { content: "</%content>"; }</style>',
+				'<style>.foo { content: "</%content>"; }</style>',
+			),
+
+			// RCDATA elements (TITLE, TEXTAREA): Content is processed but placeholder
+			// patterns are not recognized - they're treated as literal text and escaped.
+			'TITLE content placeholder escaped'    => array(
+				'<title>Hello </%name></title>',
+				'<title>Hello &lt;/%name&gt;</title>',
+			),
+
+			'TEXTAREA content placeholder escaped' => array(
+				'<textarea></%placeholder></textarea>',
+				'<textarea>&lt;/%placeholder&gt;</textarea>',
+			),
+		);
+	}
+
+	/**
+	 * Verifies leading newline behavior in PRE elements.
+	 *
+	 * HTML5 specifies that a single leading newline immediately after the
+	 * <pre> start tag is ignored. This test documents the template behavior.
+	 *
+	 * @ticket 60229
+	 *
+	 * @dataProvider data_pre_element_leading_newline
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_pre_element_leading_newline_behavior( string $template_string, array $replacements, string $expected ) {
+		$this->markTestSkipped( 'PRE newline handling is not yet correct.' );
+
+		$result = T::from( $template_string )->bind( $replacements )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	public static function data_pre_element_leading_newline() {
+		return array(
+			'PRE without newline'                         => array(
+				'<pre></%code></pre>',
+				array( 'code' => "line1\nline2" ),
+				"<pre>line1\nline2</pre>",
+			),
+
+			'PRE with newline'                            => array(
+				"<pre>\n</%code></pre>",
+				array( 'code' => "line1\nline2" ),
+				"<pre>line1\nline2</pre>",
+			),
+
+			'PRE with newline in replacement'             => array(
+				"<pre>\n</%code></pre>",
+				array( 'code' => "line1\nline2" ),
+				"<pre>line1\nline2</pre>",
+			),
+
+			'PRE with newline and newline in replacement' => array(
+				"<pre>\n</%code></pre>",
+				array( 'code' => "\nline1\nline2" ),
+				"<pre>\n\nline1\nline2</pre>",
+			),
+
+			'PRE with newline, newline replacement, and additional contents' => array(
+				"<pre>\n</%code><!--c--></pre>",
+				array( 'code' => "\nline1" ),
+				"<pre>\n\nline1<!--c--></pre>",
+			),
+		);
+	}
+
+	/**
+	 * Verifies bind() warns on missing replacement key.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::bind
+	 *
+	 * @expectedIncorrectUsage WP_HTML_Template::bind
+	 */
+	public function test_bind_warns_on_missing_key() {
+		$template = T::from( '<p></%name> </%age></p>' );
+		$template->bind( array( 'name' => 'Alice' ) );
+	}
+
+	/**
+	 * Verifies bind() warns on unused replacement key.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::bind
+	 *
+	 * @expectedIncorrectUsage WP_HTML_Template::bind
+	 */
+	public function test_bind_warns_on_unused_key() {
+		$template = T::from( '<p></%name></p>' );
+		$template->bind(
+			array(
+				'name'  => 'Alice',
+				'extra' => 'ignored',
+			)
+		);
+	}
+
+	/**
+	 * Verifies bind() warns when template used in attribute context.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::bind
+	 *
+	 * @expectedIncorrectUsage WP_HTML_Template::bind
+	 */
+	public function test_bind_warns_on_template_in_attribute_context() {
+		$template = T::from( '<meta content="</%html>">' );
+		$template->bind( array( 'html' => T::from( '<b>nested</b>' ) ) );
+	}
+
+	/**
+	 * Verifies that static text around placeholders in attributes is escaped.
+	 *
+	 * @ticket 60229
+	 *
+	 * @dataProvider data_escapes_static_text_around_placeholder_in_attribute
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_escapes_static_text_around_placeholder_in_attribute( string $template_string, array $replacements, string $expected ) {
+		$result = T::from( $template_string )->bind( $replacements )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	public static function data_escapes_static_text_around_placeholder_in_attribute() {
+		return array(
+			'leading static text (prefix before placeholder)' => array(
+				'<a href="/path/</%slug>">Link</a>',
+				array( 'slug' => 'hello' ),
+				'<a href="/path/hello">Link</a>',
+			),
+
+			'trailing static text (suffix after placeholder)' => array(
+				'<a href="</%slug>/page">Link</a>',
+				array( 'slug' => 'hello' ),
+				'<a href="hello/page">Link</a>',
+			),
+
+			'ampersand in trailing static text must be escaped' => array(
+				'<a href="</%base>&amp;extra=1">Link</a>',
+				array( 'base' => '/search?q=test' ),
+				'<a href="/search?q=test&amp;extra=1">Link</a>',
+			),
+
+			'ampersand entity in leading static text not double-escaped' => array(
+				'<a href="/search?a=1&amp;b=</%val>">Link</a>',
+				array( 'val' => '2' ),
+				'<a href="/search?a=1&amp;b=2">Link</a>',
+			),
+
+			'character reference in trailing static text preserved' => array(
+				'<meta name="</%placeholder>&not;">',
+				array( 'placeholder' => '' ),
+				'<meta name="¬">',
+			),
+
+			'two placeholders in href'               => array(
+				'<a href="</%base>/</%slug>">link</a>',
+				array(
+					'base' => '/posts',
+					'slug' => 'hello-world',
+				),
+				'<a href="/posts/hello-world">link</a>',
+			),
+
+			'three placeholders building URL'        => array(
+				'<a href="</%scheme>://</%host>/</%path>">link</a>',
+				array(
+					'scheme' => 'https',
+					'host'   => 'example.com',
+					'path'   => 'page',
+				),
+				'<a href="https://example.com/page">link</a>',
+			),
+
+			'adjacent placeholders (no separator)'   => array(
+				'<meta content="</%a></%b>">',
+				array(
+					'a' => 'Hello',
+					'b' => 'World',
+				),
+				'<meta content="HelloWorld">',
+			),
+
+			'placeholders with static text between'  => array(
+				'<a href="</%base>?page=</%page>&sort=</%sort>">link</a>',
+				array(
+					'base' => '/search',
+					'page' => '2',
+					'sort' => 'date',
+				),
+				'<a href="/search?page=2&amp;sort=date">link</a>',
+			),
+
+			'same placeholder repeated in attribute' => array(
+				'<meta content="</%val>-</%val>">',
+				array( 'val' => 'test' ),
+				'<meta content="test-test">',
+			),
+
+			'escaping in multiple placeholders'      => array(
+				'<a href="</%base>?q=</%query>">link</a>',
+				array(
+					'base'  => '/search',
+					'query' => 'a&b<c>"d',
+				),
+				'<a href="/search?q=a&amp;b&lt;c&gt;&quot;d">link</a>',
+			),
+
+			'multiple placeholders across multiple attributes' => array(
+				'<a href="</%url>" title="</%a> &amp; </%b>">link</a>',
+				array(
+					'url' => '/page',
+					'a'   => 'Alice',
+					'b'   => 'Bob',
+				),
+				'<a href="/page" title="Alice &amp; Bob">link</a>',
+			),
+		);
+	}
+
+	/**
+	 * @ticket 60229
+	 */
+	public function test_warns_on_unrecognized_replacements() {
+		$this->setExpectedIncorrectUsage( 'WP_HTML_Template::bind' );
+		$template = T::from( '<meta>' );
+		$template->bind( array( 'extra' => 'oops' ) );
+	}
+
+	/**
+	 * @ticket 60229
+	 */
+	public function test_warns_on_omit_replacement() {
+		$this->setExpectedIncorrectUsage( 'WP_HTML_Template::bind' );
+		$template = T::from( '</% omitted >' );
+		$template->bind( array() );
+	}
+
+	/**
+	 * Verifies that boolean true creates a boolean attribute.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_boolean_true_creates_boolean_attribute() {
+		$result = T::from( '<input disabled="</%disabled>">' )
+			->bind( array( 'disabled' => true ) )
+			->render();
+		$this->assertEqualHTML( '<input disabled>', $result );
+	}
+
+	/**
+	 * Verifies that boolean false removes the attribute.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_boolean_false_removes_attribute() {
+		$result = T::from( '<input disabled="</%disabled>" type="text">' )
+			->bind( array( 'disabled' => false ) )
+			->render();
+		$this->assertEqualHTML( '<input type="text">', $result );
+	}
+
+	/**
+	 * Verifies that null removes the attribute (same as false).
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_null_removes_attribute() {
+		$result = T::from( '<input class="</%class>" type="text">' )
+			->bind( array( 'class' => null ) )
+			->render();
+		$this->assertEqualHTML( '<input type="text">', $result );
+	}
+
+	/**
+	 * Verifies that boolean with partial placeholder returns false.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_partial_placeholder_rejects_boolean() {
+		$result = T::from( '<input class="prefix-</%suffix>">' )
+			->bind( array( 'suffix' => true ) )
+			->render();
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * @ticket 60229
+	 *
+	 * @dataProvider data_boolean_attribute_handling
+	 *
+	 * @covers ::from
+	 * @covers ::bind
+	 * @covers ::render
+	 */
+	public function test_boolean_attribute_handling( string $template, array $replacements, string $expected ) {
+		$result = T::from( $template )->bind( $replacements )->render();
+		$this->assertEqualHTML( $expected, $result );
+	}
+
+	public static function data_boolean_attribute_handling() {
+		return array(
+			'true creates boolean attribute'            => array(
+				'<input disabled="</%disabled>">',
+				array( 'disabled' => true ),
+				'<input disabled>',
+			),
+
+			'false removes attribute'                   => array(
+				'<input disabled="</%disabled>" type="text">',
+				array( 'disabled' => false ),
+				'<input type="text">',
+			),
+
+			'null removes attribute'                    => array(
+				'<input class="</%class>" type="text">',
+				array( 'class' => null ),
+				'<input type="text">',
+			),
+
+			'empty string keeps attribute with empty value' => array(
+				'<input value="</%value>">',
+				array( 'value' => '' ),
+				'<input value="">',
+			),
+
+			'mixed boolean and string replacements'     => array(
+				'<input disabled="</%d>" value="</%v>">',
+				array(
+					'd' => true,
+					'v' => 'test',
+				),
+				'<input disabled value="test">',
+			),
+
+			'multiple attributes, one removed'          => array(
+				'<input class="</%c>" id="</%i>" name="field">',
+				array(
+					'c' => false,
+					'i' => 'my-id',
+				),
+				'<input id="my-id" name="field">',
+			),
+
+			'single-quoted attribute with boolean'      => array(
+				"<input disabled='</%disabled>'>",
+				array( 'disabled' => true ),
+				'<input disabled>',
+			),
+		);
+	}
+
+	/**
+	 * Verifies render() returns false for integer replacement value.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::render
+	 */
+	public function test_render_returns_false_for_integer_replacement() {
+		$result = T::from( '<p></%val></p>' )->bind( array( 'val' => 123 ) )->render();
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * Verifies render() returns false for array replacement value.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::render
+	 */
+	public function test_render_returns_false_for_array_replacement() {
+		$result = T::from( '<p></%val></p>' )->bind( array( 'val' => array( 'a', 'b' ) ) )->render();
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * Verifies render() returns false for object replacement value without __toString.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::render
+	 */
+	public function test_render_returns_false_for_object_replacement() {
+		$result = T::from( '<p></%val></p>' )->bind( array( 'val' => new stdClass() ) )->render();
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * Verifies render() returns false for null replacement value.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::render
+	 */
+	public function test_render_returns_false_for_null_replacement() {
+		$result = T::from( '<p></%val></p>' )->bind( array( 'val' => null ) )->render();
+		$this->assertFalse( $result );
+	}
+
+	/**
+	 * Verifies render() returns false for boolean replacement value.
+	 *
+	 * @ticket 60229
+	 *
+	 * @covers ::render
+	 */
+	public function test_render_returns_false_for_boolean_replacement() {
+		$result = T::from( '<p></%val></p>' )->bind( array( 'val' => true ) )->render();
+		$this->assertFalse( $result );
+	}
+}