diff --git a/.github/workflows/sync_default_gems.yml b/.github/workflows/sync_default_gems.yml
index 3912f567e388cc..3a811be18a3187 100644
--- a/.github/workflows/sync_default_gems.yml
+++ b/.github/workflows/sync_default_gems.yml
@@ -30,12 +30,8 @@ jobs:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         name: Check out ruby/ruby
         with:
-          fetch-depth: 999999 # Fetch all history to follow past renames. Not using 0 to avoid fetching tags/branches.
           token: ${{ github.repository == 'ruby/ruby' && secrets.MATZBOT_AUTO_UPDATE_TOKEN || secrets.GITHUB_TOKEN }}
 
-      - name: Increase rename limit
-        run: git config merge.renameLimit 999999
-
       - name: Run tool/sync_default_gems.rb
         id: sync
         run: |
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index af849720575652..86e951bcb77e46 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -173,7 +173,7 @@ jobs:
 
       - uses: ./.github/actions/slack
         with:
-          label: ${{ matrix.test_task }} ${{ matrix.configure }}${{ matrix.arch }}
+          label: ${{ matrix.test_task }} ${{ matrix.configure }}${{ matrix.arch }}${{ matrix.os }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
         if: ${{ failure() }}
 
diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index c577f4981470a4..6ee6bc76aec8ff 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -143,7 +143,7 @@ def help(cli = nil)
     end
 
     def self.handle_no_command_error(command, has_namespace = $thor_runner)
-      if Bundler.feature_flag.plugins? && Bundler::Plugin.command?(command)
+      if Bundler.settings[:plugins] && Bundler::Plugin.command?(command)
         return Bundler::Plugin.exec_command(command, ARGV[1..-1])
       end
 
@@ -623,7 +623,7 @@ def pristine(*gems)
       end
     end
 
-    if Bundler.feature_flag.plugins?
+    if Bundler.settings[:plugins]
       require_relative "cli/plugin"
       desc "plugin", "Manage the bundler plugins"
       subcommand "plugin", Plugin
diff --git a/lib/bundler/cli/install.rb b/lib/bundler/cli/install.rb
index 57c28379e5f57d..20e22155de8ee9 100644
--- a/lib/bundler/cli/install.rb
+++ b/lib/bundler/cli/install.rb
@@ -38,7 +38,7 @@ def run
 
       Bundler::Fetcher.disable_endpoint = options["full-index"]
 
-      Plugin.gemfile_install(Bundler.default_gemfile) if Bundler.feature_flag.plugins?
+      Plugin.gemfile_install(Bundler.default_gemfile) if Bundler.settings[:plugins]
 
       # For install we want to enable strict validation
       # (rather than some optimizations we perform at app runtime).
diff --git a/lib/bundler/cli/update.rb b/lib/bundler/cli/update.rb
index 13f576cfa75b15..cf0ceac0bd19c5 100644
--- a/lib/bundler/cli/update.rb
+++ b/lib/bundler/cli/update.rb
@@ -15,7 +15,7 @@ def run
 
       Bundler.self_manager.update_bundler_and_restart_with_it_if_needed(update_bundler) if update_bundler
 
-      Plugin.gemfile_install(Bundler.default_gemfile) if Bundler.feature_flag.plugins?
+      Plugin.gemfile_install(Bundler.default_gemfile) if Bundler.settings[:plugins]
 
       sources = Array(options[:source])
       groups  = Array(options[:group]).map(&:to_sym)
diff --git a/lib/bundler/feature_flag.rb b/lib/bundler/feature_flag.rb
index b2b134889573c1..c3b8d790fbbce9 100644
--- a/lib/bundler/feature_flag.rb
+++ b/lib/bundler/feature_flag.rb
@@ -27,8 +27,6 @@ def self.settings_method(name, key, &default)
 
     (1..10).each {|v| define_method("bundler_#{v}_mode?") { @major_version >= v } }
 
-    settings_flag(:global_gem_cache) { bundler_5_mode? }
-    settings_flag(:plugins) { @bundler_version >= Gem::Version.new("1.14") }
     settings_flag(:update_requires_all_flag) { bundler_5_mode? }
 
     settings_option(:default_cli_command) { bundler_4_mode? ? :cli_help : :install }
diff --git a/lib/bundler/inline.rb b/lib/bundler/inline.rb
index f2f5b22cd381a8..4e4b51e7a5dfb4 100644
--- a/lib/bundler/inline.rb
+++ b/lib/bundler/inline.rb
@@ -51,7 +51,7 @@ def gemfile(force_latest_compatible = false, options = {}, &gemfile)
     Bundler.instance_variable_set(:@bundle_path, Pathname.new(Gem.dir))
     Bundler::SharedHelpers.set_env "BUNDLE_GEMFILE", "Gemfile"
 
-    Bundler::Plugin.gemfile_install(&gemfile) if Bundler.feature_flag.plugins?
+    Bundler::Plugin.gemfile_install(&gemfile) if Bundler.settings[:plugins]
     builder = Bundler::Dsl.new
     builder.instance_eval(&gemfile)
 
diff --git a/lib/bundler/plugin.rb b/lib/bundler/plugin.rb
index 44129cc0ff5089..fd6da6cf6dec71 100644
--- a/lib/bundler/plugin.rb
+++ b/lib/bundler/plugin.rb
@@ -220,7 +220,7 @@ def add_hook(event, &block)
     #
     # @param [String] event
     def hook(event, *args, &arg_blk)
-      return unless Bundler.feature_flag.plugins?
+      return unless Bundler.settings[:plugins]
       unless Events.defined_event?(event)
         raise ArgumentError, "Event '#{event}' not defined in Bundler::Plugin::Events"
       end
diff --git a/lib/bundler/rubygems_integration.rb b/lib/bundler/rubygems_integration.rb
index 31f255d997a833..d8f95cffb8fcd6 100644
--- a/lib/bundler/rubygems_integration.rb
+++ b/lib/bundler/rubygems_integration.rb
@@ -416,11 +416,7 @@ def path_separator
     end
 
     def all_specs
-      SharedHelpers.major_deprecation 2, "Bundler.rubygems.all_specs has been removed in favor of Bundler.rubygems.installed_specs"
-
-      Gem::Specification.stubs.map do |stub|
-        StubSpecification.from_stub(stub)
-      end
+      SharedHelpers.feature_removed! "Bundler.rubygems.all_specs has been removed in favor of Bundler.rubygems.installed_specs"
     end
 
     def installed_specs
diff --git a/lib/bundler/settings.rb b/lib/bundler/settings.rb
index 7923ba51c36630..64f0c9900eb285 100644
--- a/lib/bundler/settings.rb
+++ b/lib/bundler/settings.rb
@@ -83,6 +83,8 @@ class Settings
       "BUNDLE_VERSION" => "lockfile",
       "BUNDLE_LOCKFILE_CHECKSUMS" => true,
       "BUNDLE_CACHE_ALL" => true,
+      "BUNDLE_PLUGINS" => true,
+      "BUNDLE_GLOBAL_GEM_CACHE" => false,
     }.freeze
 
     def initialize(root = nil)
diff --git a/lib/bundler/source.rb b/lib/bundler/source.rb
index 232873503b3933..2b90a0eff1bfbb 100644
--- a/lib/bundler/source.rb
+++ b/lib/bundler/source.rb
@@ -79,7 +79,7 @@ def path?
     end
 
     def extension_cache_path(spec)
-      return unless Bundler.feature_flag.global_gem_cache?
+      return unless Bundler.settings[:global_gem_cache]
       return unless source_slug = extension_cache_slug(spec)
       Bundler.user_cache.join(
         "extensions", Gem::Platform.local.to_s, Bundler.ruby_scope,
diff --git a/lib/bundler/source/git.rb b/lib/bundler/source/git.rb
index bb12ff52f514fb..bb669ebba39d21 100644
--- a/lib/bundler/source/git.rb
+++ b/lib/bundler/source/git.rb
@@ -238,7 +238,7 @@ def load_spec_files
       # across different projects, this cache will be shared.
       # When using local git repos, this is set to the local repo.
       def cache_path
-        @cache_path ||= if Bundler.feature_flag.global_gem_cache?
+        @cache_path ||= if Bundler.settings[:global_gem_cache]
           Bundler.user_cache
         else
           Bundler.bundle_path.join("cache", "bundler")
diff --git a/lib/bundler/source/rubygems.rb b/lib/bundler/source/rubygems.rb
index fdc3a77b248072..2631c860a010ba 100644
--- a/lib/bundler/source/rubygems.rb
+++ b/lib/bundler/source/rubygems.rb
@@ -493,7 +493,7 @@ def download_gem(spec, download_cache_path, previous_spec = nil)
       # @return [Pathname] The global cache path.
       #
       def download_cache_path(spec)
-        return unless Bundler.feature_flag.global_gem_cache?
+        return unless Bundler.settings[:global_gem_cache]
         return unless remote = spec.remote
         return unless cache_slug = remote.cache_slug
 
diff --git a/lib/bundler/spec_set.rb b/lib/bundler/spec_set.rb
index 411393ce1bdd7c..4ae03171dc5813 100644
--- a/lib/bundler/spec_set.rb
+++ b/lib/bundler/spec_set.rb
@@ -179,9 +179,7 @@ def insecurely_materialized_specs
     end
 
     def -(other)
-      SharedHelpers.major_deprecation 2, "SpecSet#- has been removed with no replacement"
-
-      SpecSet.new(to_a - other.to_a)
+      SharedHelpers.feature_removed! "SpecSet#- has been removed with no replacement"
     end
 
     def find_by_name_and_platform(name, platform)
@@ -212,9 +210,7 @@ def what_required(spec)
     end
 
     def <<(spec)
-      SharedHelpers.major_deprecation 2, "SpecSet#<< has been removed with no replacement"
-
-      @specs << spec
+      SharedHelpers.feature_removed! "SpecSet#<< has been removed with no replacement"
     end
 
     def length