diff --git a/.github/workflows/install-testing.yml b/.github/workflows/install-testing.yml
index 981d2a18fb148..61bbdeecc0cf7 100644
--- a/.github/workflows/install-testing.yml
+++ b/.github/workflows/install-testing.yml
@@ -47,7 +47,7 @@ jobs:
     permissions:
       contents: read
     secrets: inherit
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     with:
       wp-version: ${{ inputs.wp-version }}
 
@@ -63,7 +63,7 @@ jobs:
     permissions:
       contents: read
     runs-on: ${{ matrix.os }}
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     timeout-minutes: 10
     needs: [ build-test-matrix ]
     strategy:
diff --git a/.github/workflows/local-docker-environment.yml b/.github/workflows/local-docker-environment.yml
index b94c5bb8e5dad..c0a70c9afb7df 100644
--- a/.github/workflows/local-docker-environment.yml
+++ b/.github/workflows/local-docker-environment.yml
@@ -73,7 +73,7 @@ jobs:
     permissions:
       contents: read
     secrets: inherit
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     with:
       wp-version: ${{ github.event_name == 'pull_request' && github.base_ref || github.ref_name }}
 
diff --git a/.github/workflows/phpunit-tests.yml b/.github/workflows/phpunit-tests.yml
index 3c55528cd13aa..cfc331cedc04b 100644
--- a/.github/workflows/phpunit-tests.yml
+++ b/.github/workflows/phpunit-tests.yml
@@ -63,7 +63,7 @@ jobs:
     permissions:
       contents: read
     secrets: inherit
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ startsWith( github.repository, 'WordPress/' ) && ( github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) ) }}
     strategy:
       fail-fast: false
       matrix:
@@ -140,7 +140,7 @@ jobs:
     permissions:
       contents: read
     secrets: inherit
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ startsWith( github.repository, 'WordPress/' ) && ( github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) ) }}
     strategy:
       fail-fast: false
       matrix:
@@ -192,7 +192,7 @@ jobs:
     permissions:
       contents: read
     secrets: inherit
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ startsWith( github.repository, 'WordPress/' ) && ( github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) ) }}
     strategy:
       fail-fast: false
       matrix:
@@ -232,7 +232,7 @@ jobs:
     permissions:
       contents: read
     secrets: inherit
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ startsWith( github.repository, 'WordPress/' ) && ( github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) ) }}
     strategy:
       fail-fast: false
       matrix:
@@ -246,13 +246,71 @@ jobs:
       db-version: ${{ matrix.db-version }}
       phpunit-test-groups: ${{ matrix.phpunit-test-groups }}
 
+  #
+  # Runs unit tests for forks.
+  #
+  # Because the majority of forks will belong to personal GitHub accounts (which are limited to just 20 concurrent jobs
+  # at any given time), forks only run a small subset of test combinations. This allows contributors to open pull
+  # requests back to their own forks for testing purposes without having to wait hours for workflow to complete.
+  #
+  limited-matrix-for-forks:
+    name: PHP ${{ matrix.php }}
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
+    permissions:
+      contents: read
+    secrets: inherit
+    if: ${{ ! startsWith( github.repository, 'WordPress/' ) && github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' }}
+    strategy:
+      fail-fast: false
+      matrix:
+        php: [ '7.2', '8.4' ]
+        db-version: [ '8.4', '11.8' ]
+        db-type: [ 'mysql', 'mariadb' ]
+        multisite: [ false ]
+
+        include:
+          # Include one multisite job for each database type.
+          - php: '8.4'
+            db-version: '8.4'
+            db-type: 'mysql'
+            multisite: true
+          - php: '8.4'
+            db-version: '11.8'
+            db-type: 'mariadb'
+            multisite: true
+          # Test with memcached.
+          - php: '8.4'
+            db-version: '8.4'
+            db-type: 'mysql'
+            multisite: true
+            memcached: true
+          # Run specific test groups once.
+          - php: '8.4'
+            db-version: '8.4'
+            db-type: 'mysql'
+            phpunit-test-groups: 'html-api-html5lib-tests'
+
+        exclude:
+          # Exclude PHP versions that are not supported by the database versions.
+          - db-type: 'mysql'
+            db-version: '11.8'
+          - db-type: 'mariadb'
+            db-version: '8.4'
+
+    with:
+      php: ${{ matrix.php }}
+      db-version: ${{ matrix.db-version }}
+      db-type: ${{ matrix.db-type }}
+      memcached: ${{ matrix.memcached || false }}
+      phpunit-test-groups: ${{ matrix.phpunit-test-groups || '' }}
+
   slack-notifications:
     name: Slack Notifications
     uses: ./.github/workflows/slack-notifications.yml
     permissions:
       actions: read
       contents: read
-    needs: [ test-with-mysql, test-with-mariadb, test-innovation-releases, specific-test-groups ]
+    needs: [ test-with-mysql, test-with-mariadb, test-innovation-releases, specific-test-groups, limited-matrix-for-forks ]
     if: ${{ github.repository == 'WordPress/wordpress-develop' && github.event_name != 'pull_request' && always() }}
     with:
       calling_status: ${{ contains( needs.*.result, 'cancelled' ) && 'cancelled' || contains( needs.*.result, 'failure' ) && 'failure' || 'success' }}
diff --git a/.github/workflows/test-and-zip-default-themes.yml b/.github/workflows/test-and-zip-default-themes.yml
index 49b7522cfe1a7..56cc2e9895cd2 100644
--- a/.github/workflows/test-and-zip-default-themes.yml
+++ b/.github/workflows/test-and-zip-default-themes.yml
@@ -189,7 +189,7 @@ jobs:
       contents: read
     needs: [ check-for-empty-files, test-build-scripts ]
     timeout-minutes: 10
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || github.event_name == 'pull_request' }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/test-build-processes.yml b/.github/workflows/test-build-processes.yml
index 966a458550dc3..559dd0a92a1c4 100644
--- a/.github/workflows/test-build-processes.yml
+++ b/.github/workflows/test-build-processes.yml
@@ -45,7 +45,7 @@ concurrency:
 permissions: {}
 
 jobs:
-  # Tests the WordPress Core build process on multiple operating systems.
+  # Tests the WordPress Core build process.
   test-core-build-process:
     name: Core running from ${{ matrix.directory }}
     uses: ./.github/workflows/reusable-test-core-build-process.yml
@@ -55,30 +55,31 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-24.04, windows-2022 ]
+        os: [ 'ubuntu-24.04' ]
         directory: [ 'src', 'build' ]
         include:
           # Only prepare artifacts for Playground once.
-          - os: ubuntu-24.04
+          - os: 'ubuntu-24.04'
             directory: 'build'
             save-build: true
             prepare-playground: ${{ github.event_name == 'pull_request' && true || '' }}
-
     with:
       os: ${{ matrix.os }}
       directory: ${{ matrix.directory }}
       save-build: ${{ matrix.save-build && matrix.save-build || false }}
       prepare-playground: ${{ matrix.prepare-playground && matrix.prepare-playground || false }}
 
-  # Tests the WordPress Core build process on MacOS.
+  # Tests the WordPress Core build process on additional operating systems.
   #
-  # This is separate from the job above in order to use stricter conditions when determining when to run.
-  # This avoids unintentionally consuming excessive minutes, as MacOS jobs consume minutes at a 10x rate.
+  # This is separate from the job above in order to use stricter conditions when determining when to test additional
+  # operating systems. This avoids unintentionally consuming excessive minutes. Windows-based jobs consume minutes at a
+  # 2x rate, and MacOS-based jobs at a 10x rate.
+  # See https://docs.github.com/en/billing/concepts/product-billing/github-actions#per-minute-rates.
   #
   # The `matrix` and `runner` contexts are not available for use within `if` expressions. So there is
   # currently no way to determine the OS being used on a given job.
   # See https://docs.github.com/en/actions/learn-github-actions/contexts#context-availability.
-  test-core-build-process-macos:
+  test-core-build-process-additional-os:
     name: Core running from ${{ matrix.directory }}
     uses: ./.github/workflows/reusable-test-core-build-process.yml
     permissions:
@@ -87,37 +88,39 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ macos-14 ]
+        os: [ 'macos-14', 'windows-2022' ]
         directory: [ 'src', 'build' ]
     with:
       os: ${{ matrix.os }}
       directory: ${{ matrix.directory }}
 
-  # Tests the Gutenberg plugin build process on multiple operating systems when run within a wordpress-develop checkout.
+  # Tests the Gutenberg plugin build process within a wordpress-develop checkout.
   test-gutenberg-build-process:
     name: Gutenberg running from ${{ matrix.directory }}
     uses: ./.github/workflows/reusable-test-gutenberg-build-process.yml
     permissions:
       contents: read
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-24.04, windows-2022 ]
+        os: [ 'ubuntu-24.04' ]
         directory: [ 'src', 'build' ]
     with:
       os: ${{ matrix.os }}
       directory: ${{ matrix.directory }}
 
-  # Tests the Gutenberg plugin build process on MacOS when run within a wordpress-develop checkout.
+  # Tests the Gutenberg plugin build process on additional operating systems.
   #
-  # This is separate from the job above in order to use stricter conditions when determining when to run.
-  # This avoids unintentionally consuming excessive minutes, as MacOS jobs consume minutes at a 10x rate.
+  # This is separate from the job above in order to use stricter conditions when determining when to test additional
+  # operating systems. This avoids unintentionally consuming excessive minutes. Windows-based jobs consume minutes at a
+  # 2x rate, and MacOS-based jobs at a 10x rate.
+  # See https://docs.github.com/en/billing/concepts/product-billing/github-actions#per-minute-rates.
   #
   # The `matrix` and `runner` contexts are not available for use within `if` expressions. So there is
   # currently no way to determine the OS being used on a given job.
   # See https://docs.github.com/en/actions/learn-github-actions/contexts#context-availability.
-  test-gutenberg-build-process-macos:
+  test-gutenberg-build-process-additional-os:
     name: Gutenberg running from ${{ matrix.directory }}
     uses: ./.github/workflows/reusable-test-gutenberg-build-process.yml
     permissions:
@@ -126,7 +129,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ macos-14 ]
+        os: [ 'macos-14', 'windows-2022' ]
         directory: [ 'src', 'build' ]
     with:
       os: ${{ matrix.os }}
@@ -138,7 +141,7 @@ jobs:
     permissions:
       actions: read
       contents: read
-    needs: [ test-core-build-process, test-core-build-process-macos, test-gutenberg-build-process, test-gutenberg-build-process-macos ]
+    needs: [ test-core-build-process, test-core-build-process-additional-os, test-gutenberg-build-process, test-gutenberg-build-process-additional-os ]
     if: ${{ github.repository == 'WordPress/wordpress-develop' && github.event_name != 'pull_request' && always() }}
     with:
       calling_status: ${{ contains( needs.*.result, 'cancelled' ) && 'cancelled' || contains( needs.*.result, 'failure' ) && 'failure' || 'success' }}
diff --git a/.github/workflows/upgrade-develop-testing.yml b/.github/workflows/upgrade-develop-testing.yml
index b24fd5fea220d..ad5211f271f4d 100644
--- a/.github/workflows/upgrade-develop-testing.yml
+++ b/.github/workflows/upgrade-develop-testing.yml
@@ -47,6 +47,7 @@ jobs:
   build:
     name: Build
     uses: ./.github/workflows/reusable-build-package.yml
+    if: ${{ startsWith( github.repository, 'WordPress/' ) && ( github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) ) }}
     permissions:
       contents: read
 
@@ -54,7 +55,7 @@ jobs:
   upgrade-tests-develop:
     name: Upgrade from ${{ matrix.wp }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     needs: [ build ]
     strategy:
       fail-fast: false
@@ -83,6 +84,36 @@ jobs:
       new-version: develop
       multisite: ${{ matrix.multisite }}
 
+  # Run a limited set of upgrade tests for the current branch on forks.
+  upgrade-tests-develop-forks:
+    name: Upgrade from ${{ matrix.wp }}
+    uses: ./.github/workflows/reusable-upgrade-testing.yml
+    if: ${{ github.repository != 'WordPress/wordpress-develop' }}
+    needs: [ build ]
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ 'ubuntu-24.04' ]
+        php: [ '7.2', '8.4' ]
+        db-type: [ 'mysql' ]
+        db-version: [ '8.4' ]
+        # WordPress 4.9 is the oldest version that supports PHP 7.2.
+        wp: [ '6.7', '6.8' ]
+        multisite: [ false, true ]
+
+        exclude:
+          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
+          - php: '7.2'
+            db-version: '8.4'
+    with:
+      os: ${{ matrix.os }}
+      php: ${{ matrix.php }}
+      db-type: ${{ matrix.db-type }}
+      db-version: ${{ matrix.db-version }}
+      wp: ${{ matrix.wp }}
+      new-version: develop
+      multisite: ${{ matrix.multisite }}
+
   slack-notifications:
     name: Slack Notifications
     uses: ./.github/workflows/slack-notifications.yml
diff --git a/.github/workflows/upgrade-testing.yml b/.github/workflows/upgrade-testing.yml
index 6090d48eb0ce6..c31a296ecbada 100644
--- a/.github/workflows/upgrade-testing.yml
+++ b/.github/workflows/upgrade-testing.yml
@@ -58,7 +58,7 @@ jobs:
   upgrade-tests-recent-releases:
     name: ${{ matrix.wp }} to ${{ inputs.new-version && inputs.new-version || 'latest' }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
@@ -93,7 +93,7 @@ jobs:
   upgrade-tests-wp-6x-mysql:
     name: ${{ matrix.wp }} to ${{ inputs.new-version && inputs.new-version || 'latest' }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
@@ -121,7 +121,7 @@ jobs:
   upgrade-tests-wp-5x-php-7x-mysql:
     name: ${{ matrix.wp }} to ${{ inputs.new-version && inputs.new-version || 'latest' }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
@@ -153,7 +153,7 @@ jobs:
   upgrade-tests-wp-5x-php-8x-mysql:
     name: ${{ matrix.wp }} to ${{ inputs.new-version && inputs.new-version || 'latest' }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
@@ -181,7 +181,7 @@ jobs:
   upgrade-tests-oldest-wp-mysql:
     name: ${{ matrix.wp }} to ${{ inputs.new-version && inputs.new-version || 'latest' }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
-    if: ${{ github.repository == 'WordPress/wordpress-develop' || ( github.event_name == 'pull_request' && github.actor != 'dependabot[bot]' ) }}
+    if: ${{ github.repository == 'WordPress/wordpress-develop' }}
     strategy:
       fail-fast: false
       matrix:
diff --git a/src/wp-activate.php b/src/wp-activate.php
index f4fd8d76c31a7..2ba58ee76f131 100644
--- a/src/wp-activate.php
+++ b/src/wp-activate.php
@@ -23,6 +23,7 @@
 list( $activate_path ) = explode( '?', wp_unslash( $_SERVER['REQUEST_URI'] ) );
 $activate_cookie       = 'wp-activate-' . COOKIEHASH;
 
+
 $key    = '';
 $result = null;