diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/BackoffStrategy.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/BackoffStrategy.java
index 6dc936081f..656f7f56e1 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/BackoffStrategy.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/BackoffStrategy.java
@@ -38,7 +38,7 @@ public interface BackoffStrategy {
      * @param attempt           consecutive reconnect attempt number (1-based)
      * @param previousDelayMs   last delay used (0 for first attempt)
      * @param serverRetryHintMs value from server 'retry:' (ms) or HTTP Retry-After, or null if none
-     * @return delay in milliseconds (>= 0)
+     * @return delay in milliseconds, greater than or equal to {@code 0}
      */
     long nextDelayMs(int attempt, long previousDelayMs, Long serverRetryHintMs);
 
@@ -49,7 +49,7 @@ public interface BackoffStrategy {
      * @param attempt           consecutive reconnect attempt number (1-based)
      * @param previousDelayMs   last delay used (0 for first attempt)
      * @param serverRetryHintMs value from server 'retry:' (ms) or HTTP Retry-After, or null if none
-     * @return true to reconnect, false to stop
+     * @return {@code true} to reconnect, {@code false} to stop
      */
     default boolean shouldReconnect(final int attempt, final long previousDelayMs, final Long serverRetryHintMs) {
         return true;
diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/EventSourceListener.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/EventSourceListener.java
index 81de3223e6..327cd21835 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/EventSourceListener.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/EventSourceListener.java
@@ -33,7 +33,7 @@
  * <p>Implementations should keep handlers lightweight and non-blocking.
  * If you need to do heavy work, offload to your own executor.</p>
  *
- * <h3>Invocation & threading</h3>
+ * <h3>Invocation &amp; threading</h3>
  * <ul>
  *   <li>Methods may be invoked on an internal callback executor supplied to the
  *       {@code EventSource} (or on the caller thread if none was supplied).
diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutor.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutor.java
index 69fa3447af..c9d92dc470 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutor.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutor.java
@@ -126,6 +126,7 @@ static CloseableHttpAsyncClient getSharedClient() {
      *
      * <p>Use this when you want to set defaults such as headers, backoff,
      * parser strategy (char vs. byte), or custom executors for scheduling and callbacks.</p>
+     * @return a new {@link SseExecutorBuilder}
      */
     public static SseExecutorBuilder custom() {
         return new SseExecutorBuilder();
@@ -137,6 +138,7 @@ public static SseExecutorBuilder custom() {
      * <p>Streams opened by this executor will share one underlying {@link CloseableHttpAsyncClient}
      * instance. {@link #close()} will be a no-op; call {@link #closeSharedClient()} to
      * explicitly shut the shared client down (for tests / application shutdown).</p>
+     * @return a new {@link SseExecutor}
      */
     public static SseExecutor newInstance() {
         final CloseableHttpAsyncClient c = getSharedClient();
@@ -152,6 +154,8 @@ public static SseExecutor newInstance() {
      * @param client an already constructed async client
      * @throws NullPointerException  if {@code client} is {@code null}
      * @throws IllegalStateException if the client is shutting down or shut down
+     * @return a new {@link SseExecutor}
+     *
      */
     public static SseExecutor newInstance(final CloseableHttpAsyncClient client) {
         Args.notNull(client, "HTTP Async Client");
@@ -164,6 +168,7 @@ public static SseExecutor newInstance(final CloseableHttpAsyncClient client) {
      * Closes and clears the shared async client, if present.
      *
      * <p>Useful for tests or orderly application shutdown.</p>
+     * @throws IOException if closing the client fails
      */
     public static void closeSharedClient() throws IOException {
         LOCK.lock();
@@ -213,6 +218,7 @@ public static void closeSharedClient() throws IOException {
     /**
      * Closes the underlying async client if this executor does <em>not</em> use
      * the process-wide shared client. No-op otherwise.
+     * @throws IOException if closing the client fails
      */
     public void close() throws IOException {
         if (!isSharedClient) {
@@ -225,6 +231,7 @@ public void close() throws IOException {
      *
      * @param uri      target SSE endpoint (must produce {@code text/event-stream})
      * @param listener event callbacks
+     * @return the created {@link EventSource}
      */
     public EventSource open(final URI uri, final EventSourceListener listener) {
         return open(uri, this.defaultHeaders, listener, this.defaultConfig,
@@ -237,6 +244,7 @@ public EventSource open(final URI uri, final EventSourceListener listener) {
      * @param uri      target SSE endpoint
      * @param headers  extra request headers (merged with executor defaults)
      * @param listener event callbacks
+     * @return the created {@link EventSource}
      */
     public EventSource open(final URI uri,
                             final Map<String, String> headers,
@@ -252,6 +260,7 @@ public EventSource open(final URI uri,
      * @param headers  extra request headers (merged with executor defaults)
      * @param listener event callbacks
      * @param config   reconnect/backoff config
+     * @return the created {@link EventSource}
      */
     public EventSource open(final URI uri,
                             final Map<String, String> headers,
@@ -271,6 +280,7 @@ public EventSource open(final URI uri,
      * @param parser           parsing strategy ({@link SseParser#CHAR} or {@link SseParser#BYTE})
      * @param scheduler        scheduler for reconnects (nullable → internal shared scheduler)
      * @param callbackExecutor executor for listener callbacks (nullable → run inline)
+     * @return the created {@link EventSource}
      */
     public EventSource open(final URI uri,
                             final Map<String, String> headers,
@@ -292,6 +302,7 @@ public EventSource open(final URI uri,
 
     /**
      * Returns the underlying {@link CloseableHttpAsyncClient}.
+     * @return the client
      */
     public CloseableHttpAsyncClient getClient() {
         return client;
diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutorBuilder.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutorBuilder.java
index b03356513f..0109f5a099 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutorBuilder.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/SseExecutorBuilder.java
@@ -77,6 +77,8 @@ public final class SseExecutorBuilder {
     /**
      * Supplies a custom async HTTP client. The caller owns its lifecycle and
      * {@link SseExecutor#close()} will close it.
+     * @param client the client to use
+     * @return this builder
      */
     public SseExecutorBuilder setHttpClient(final CloseableHttpAsyncClient client) {
         this.client = Args.notNull(client, "HTTP Async Client");
@@ -86,6 +88,8 @@ public SseExecutorBuilder setHttpClient(final CloseableHttpAsyncClient client) {
     /**
      * Sets the scheduler to use for reconnect delays. If not provided, the internal shared
      * scheduler is used.
+     * @param scheduler the scheduler to use
+     * @return this builder
      */
     public SseExecutorBuilder setScheduler(final ScheduledExecutorService scheduler) {
         this.scheduler = scheduler;
@@ -95,6 +99,8 @@ public SseExecutorBuilder setScheduler(final ScheduledExecutorService scheduler)
     /**
      * Sets the executor used to dispatch {@link EventSourceListener} callbacks.
      * If not provided, callbacks run inline on the I/O thread.
+     * @param callbackExecutor the executor to use
+     * @return this builder
      */
     public SseExecutorBuilder setCallbackExecutor(final Executor callbackExecutor) {
         this.callbackExecutor = callbackExecutor;
@@ -103,6 +109,8 @@ public SseExecutorBuilder setCallbackExecutor(final Executor callbackExecutor) {
 
     /**
      * Sets the default reconnect/backoff configuration applied to opened streams.
+     * @param cfg the reconnect configuration
+     * @return this builder
      */
     public SseExecutorBuilder setEventSourceConfig(final EventSourceConfig cfg) {
         this.config = Args.notNull(cfg, "EventSourceConfig");
@@ -111,6 +119,8 @@ public SseExecutorBuilder setEventSourceConfig(final EventSourceConfig cfg) {
 
     /**
      * Replaces the default headers (sent on every opened stream).
+     * @param headers the headers to use
+     * @return this builder
      */
     public SseExecutorBuilder setDefaultHeaders(final Map<String, String> headers) {
         this.defaultHeaders.clear();
@@ -122,6 +132,9 @@ public SseExecutorBuilder setDefaultHeaders(final Map<String, String> headers) {
 
     /**
      * Adds or replaces a single default header.
+     * @param name the header name
+     * @param value the header value
+     * @return this builder
      */
     public SseExecutorBuilder addDefaultHeader(final String name, final String value) {
         this.defaultHeaders.put(Args.notNull(name, "name"), value);
@@ -131,6 +144,8 @@ public SseExecutorBuilder addDefaultHeader(final String name, final String value
     /**
      * Chooses the parser strategy: {@link SseParser#CHAR} (spec-level, default)
      * or {@link SseParser#BYTE} (byte-level framing with minimal decoding).
+     * @param parser the parser strategy to use
+     * @return this builder
      */
     public SseExecutorBuilder setParserStrategy(final SseParser parser) {
         this.parserStrategy = parser != null ? parser : SseParser.CHAR;
@@ -139,6 +154,7 @@ public SseExecutorBuilder setParserStrategy(final SseParser parser) {
 
     /**
      * Builds the {@link SseExecutor}.
+     * @return a new {@link SseExecutor}
      */
     public SseExecutor build() {
         final CloseableHttpAsyncClient c = (client != null) ? client : SseExecutor.getSharedClient();
diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/ServerSentEventReader.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/ServerSentEventReader.java
index 9664be6c91..d674cd1c47 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/ServerSentEventReader.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/ServerSentEventReader.java
@@ -38,7 +38,6 @@
  *   <li>{@code retry} is parsed without creating a substring; only {@code data/event/id} values
  *       create substrings when needed.</li>
  * </ul>
- * </p>
  */
 @Internal
 public final class ServerSentEventReader {
diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/SseParser.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/SseParser.java
index b71d96a893..91de4c8470 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/SseParser.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/impl/SseParser.java
@@ -44,7 +44,7 @@ public enum SseParser {
      */
     CHAR,
     /**
-     * ByteBuffer → byte-level framing & minimal decode.
+     * ByteBuffer → byte-level framing &amp; minimal decode.
      */
     BYTE
 }
diff --git a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/package-info.java b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/package-info.java
index 776dd9f6b3..7c3345632f 100644
--- a/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/package-info.java
+++ b/httpclient5-sse/src/main/java/org/apache/hc/client5/http/sse/package-info.java
@@ -54,7 +54,7 @@
  * </ul>
  *
  * <h2>Quick start</h2>
- * <pre>{@code
+ * <pre>
  * import java.net.URI;
  * import java.util.Collections;
  * import org.apache.hc.client5.http.sse.*;
@@ -62,23 +62,23 @@
  * SseExecutor exec = SseExecutor.newInstance(); // shared async client
  *
  * EventSourceListener listener = new EventSourceListener() {
- *   @Override public void onOpen() { System.out.println("open"); }
- *   @Override public void onEvent(String id, String type, String data) {
+ *   &#64;Override public void onOpen() { System.out.println("open"); }
+ *   &#64;Override public void onEvent(String id, String type, String data) {
  *     System.out.println(type + " id=" + id + " data=" + data);
  *   }
- *   @Override public void onClosed() { System.out.println("closed"); }
- *   @Override public void onFailure(Throwable t, boolean willReconnect) {
+ *   &#64;Override public void onClosed() { System.out.println("closed"); }
+ *   &#64;Override public void onFailure(Throwable t, boolean willReconnect) {
  *     t.printStackTrace();
  *   }
  * };
  *
  * EventSource es = exec.open(URI.create("https://example.com/stream"),
- *                            Collections.<String,String>emptyMap(),
+ *                            Collections.&lt;String,String&gt;emptyMap(),
  *                            listener);
  * es.start();
  *
  * Runtime.getRuntime().addShutdownHook(new Thread(es::cancel));
- * }</pre>
+ * </pre>
  *
  * <h2>Configuration</h2>
  * <ul>
diff --git a/pom.xml b/pom.xml
index ff7d0b9637..a4d7617c2e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -51,7 +51,7 @@
     <tag>5.7-alpha1-SNAPSHOT</tag>
   </scm>
 
- <distributionManagement>
+  <distributionManagement>
     <site>
       <id>apache.website</id>
       <name>Apache HttpComponents Website</name>
@@ -493,6 +493,15 @@
               <title>Apache HttpClient Windows features</title>
               <packages>org.apache.hc.client5.http.impl.win*</packages>
             </group>
+            <group>
+              <title>Apache HttpClient Observations</title>
+              <packages>org.apache.hc.client5.http.observation*</packages>
+            </group>
+            <group>
+              <title>Apache HttpClient SSE</title>
+              <packages>org.apache.hc.client5.http.sse*</packages>
+            </group>
+
           </groups>
         </configuration>
         <reportSets>