Index: src/wp-admin/includes/update-core.php
===================================================================
--- src/wp-admin/includes/update-core.php	(revision 43907)
+++ src/wp-admin/includes/update-core.php	(working copy)
@@ -779,6 +779,9 @@
 	'wp-includes/js/mediaelement/renderers/soundcloud.min.js',
 	'wp-includes/js/mediaelement/renderers/twitch.js',
 	'wp-includes/js/mediaelement/renderers/twitch.min.js',
+	// 5.0.0
+	'wp-includes/js/wp-a11y.js', // Moved to: wp-includes/js/dist/a11y.js
+	'wp-includes/js/wp-a11y.min.js', // Moved to: wp-includes/js/dist/a11y.min.js
 );
 
 /**
Index: src/wp-includes/js/wp-a11y.js
===================================================================
--- src/wp-includes/js/wp-a11y.js	(revision 43907)
+++ src/wp-includes/js/wp-a11y.js	(working copy)
@@ -1,103 +0,0 @@
-/** @namespace wp */
-window.wp = window.wp || {};
-
-( function ( wp, $ ) {
-	'use strict';
-
-	var $containerPolite,
-		$containerAssertive,
-		previousMessage = '';
-
-	/**
-	 * Update the ARIA live notification area text node.
-	 *
-	 * @since 4.2.0
-	 * @since 4.3.0 Introduced the 'ariaLive' argument.
-	 *
-	 * @param {String} message    The message to be announced by Assistive Technologies.
-	 * @param {String} [ariaLive] The politeness level for aria-live. Possible values:
-	 *                            polite or assertive. Default polite.
-	 * @returns {void}
-	 */
-	function speak( message, ariaLive ) {
-		// Clear previous messages to allow repeated strings being read out.
-		clear();
-
-		// Ensure only text is sent to screen readers.
-		message = $( '<p>' ).html( message ).text();
-
-		/*
-		 * Safari 10+VoiceOver don't announce repeated, identical strings. We use
-		 * a `no-break space` to force them to think identical strings are different.
-		 * See ticket #36853.
-		 */
-		if ( previousMessage === message ) {
-			message = message + '\u00A0';
-		}
-
-		previousMessage = message;
-
-		if ( $containerAssertive && 'assertive' === ariaLive ) {
-			$containerAssertive.text( message );
-		} else if ( $containerPolite ) {
-			$containerPolite.text( message );
-		}
-	}
-
-	/**
-	 * Build the live regions markup.
-	 *
-	 * @since 4.3.0
-	 *
-	 * @param {String} ariaLive Optional. Value for the 'aria-live' attribute, default 'polite'.
-	 *
-	 * @return {Object} $container The ARIA live region jQuery object.
-	 */
-	function addContainer( ariaLive ) {
-		ariaLive = ariaLive || 'polite';
-
-		var $container = $( '<div>', {
-			'id': 'wp-a11y-speak-' + ariaLive,
-			'aria-live': ariaLive,
-			'aria-relevant': 'additions text',
-			'aria-atomic': 'true',
-			'class': 'screen-reader-text wp-a11y-speak-region'
-		});
-
-		$( document.body ).append( $container );
-		return $container;
-	}
-
-	/**
-	 * Clear the live regions.
-	 *
-	 * @since 4.3.0
-	 */
-	function clear() {
-		$( '.wp-a11y-speak-region' ).text( '' );
-	}
-
-	/**
-	 * Initialize wp.a11y and define ARIA live notification area.
-	 *
-	 * @since 4.2.0
-	 * @since 4.3.0 Added the assertive live region.
-	 */
-	$( document ).ready( function() {
-		$containerPolite = $( '#wp-a11y-speak-polite' );
-		$containerAssertive = $( '#wp-a11y-speak-assertive' );
-
-		if ( ! $containerPolite.length ) {
-			$containerPolite = addContainer( 'polite' );
-		}
-
-		if ( ! $containerAssertive.length ) {
-			$containerAssertive = addContainer( 'assertive' );
-		}
-	});
-
-	/** @namespace wp.a11y */
-	wp.a11y = wp.a11y || {};
-	wp.a11y.speak = speak;
-
-}( window.wp, window.jQuery ));
Index: src/wp-includes/script-loader.php
===================================================================
--- src/wp-includes/script-loader.php	(revision 43907)
+++ src/wp-includes/script-loader.php	(working copy)
@@ -699,8 +699,6 @@
 		'expandMenu'   => __( 'Expand Main menu' ),
 	) );
 
-	$scripts->add( 'wp-a11y', "/wp-includes/js/wp-a11y$suffix.js", array( 'jquery' ), false, 1 );
-
 	$scripts->add( 'sack', "/wp-includes/js/tw-sack$suffix.js", array(), '1.6.1', 1 );
 
 	$scripts->add( 'quicktags', "/wp-includes/js/quicktags$suffix.js", array(), false, 1 );
Index: tests/phpunit/tests/dependencies/scripts.php
===================================================================
--- tests/phpunit/tests/dependencies/scripts.php	(revision 43907)
+++ tests/phpunit/tests/dependencies/scripts.php	(working copy)
@@ -668,12 +668,18 @@
 		global $wp_scripts;
 
 		wp_default_scripts( $wp_scripts );
+		wp_default_packages( $wp_scripts );
 
 		$wp_scripts->base_url  = '';
 		$wp_scripts->do_concat = true;
 
 		$ver = get_bloginfo( 'version' );
-		$expected  = "<script type='text/javascript' src='/wp-admin/load-scripts.php?c=0&amp;load%5B%5D=jquery-core,jquery-migrate,wp-a11y&amp;ver={$ver}'></script>\n";
+
+		$expected  = "\n<script type='text/javascript'>\n";
+		$expected .= "/* <![CDATA[ */\n";
+		$expected .= "( 'fetch' in window ) || document.write( '<script src=\"/wp-includes/js/dist/vendor/wp-polyfill-fetch.min.js\"></scr' + 'ipt>' );( document.contains ) || document.write( '<script src=\"/wp-includes/js/dist/vendor/wp-polyfill-node-contains.min.js\"></scr' + 'ipt>' );( window.FormData && window.FormData.prototype.keys ) || document.write( '<script src=\"/wp-includes/js/dist/vendor/wp-polyfill-formdata.min.js\"></scr' + 'ipt>' );( Element.prototype.matches && Element.prototype.closest ) || document.write( '<script src=\"/wp-includes/js/dist/vendor/wp-polyfill-element-closest.min.js\"></scr' + 'ipt>' );/* ]]> */\n";
+		$expected .= "</script>\n";
+		$expected .= "<script type='text/javascript' src='/wp-admin/load-scripts.php?c=0&amp;load%5B%5D=jquery-core,jquery-migrate,wp-polyfill,wp-dom-ready,wp-a11y&amp;ver={$ver}'></script>\n";
 		$expected .= "<script type='text/javascript'>\nconsole.log(\"before\");\n</script>\n";
 		$expected .= "<script type='text/javascript' src='http://example.com'></script>\n";
 		$expected .= "<script type='text/javascript' src='http://example2.com'></script>\n";
@@ -697,6 +703,7 @@
 		global $wp_scripts;
 
 		wp_default_scripts( $wp_scripts );
+		wp_default_packages( $wp_scripts );
 
 		$wp_scripts->base_url  = '';
 		$wp_scripts->do_concat = true;
Index: tests/qunit/index.html
===================================================================
--- tests/qunit/index.html	(revision 43907)
+++ tests/qunit/index.html	(working copy)
@@ -24,7 +24,7 @@
 			};
 		</script>
 		<script src="../../src/wp-includes/js/wp-util.js"></script>
-		<script src="../../src/wp-includes/js/wp-a11y.js"></script>
+		<script src="../../src/wp-includes/js/dist/a11y.js"></script>
 		<script>
 			window._wpMediaModelsL10n = {"settings":{"ajaxurl":"\/wp-admin\/admin-ajax.php","post":{"id":0}}};
 		</script>