diff -r 3d4e9c994f10 -r a86126ab1dd4 wp/wp-includes/js/wp-auth-check.js
--- a/wp/wp-includes/js/wp-auth-check.js	Tue Oct 22 16:11:46 2019 +0200
+++ b/wp/wp-includes/js/wp-auth-check.js	Tue Dec 15 13:49:49 2020 +0100
@@ -4,9 +4,10 @@
  * @output wp-includes/js/wp-auth-check.js
  */
 
-/* global adminpage */
-(function($){
-	var wrap, next;
+( function( $ ) {
+	var wrap,
+		tempHidden,
+		tempHiddenTimeout;
 
 	/**
 	 * Shows the authentication form popup.
@@ -15,18 +16,18 @@
 	 * @private
 	 */
 	function show() {
-		var parent = $('#wp-auth-check'),
-			form = $('#wp-auth-check-form'),
-			noframe = wrap.find('.wp-auth-fallback-expired'),
+		var parent = $( '#wp-auth-check' ),
+			form = $( '#wp-auth-check-form' ),
+			noframe = wrap.find( '.wp-auth-fallback-expired' ),
 			frame, loaded = false;
 
 		if ( form.length ) {
 			// Add unload confirmation to counter (frame-busting) JS redirects.
-			$(window).on( 'beforeunload.wp-auth-check', function(e) {
-				e.originalEvent.returnValue = window.authcheckL10n.beforeunload;
+			$( window ).on( 'beforeunload.wp-auth-check', function( event ) {
+				event.originalEvent.returnValue = window.wp.i18n.__( 'Your session has expired. You can log in again from this page or go to the login page.' );
 			});
 
-			frame = $('<iframe id="wp-auth-check-frame" frameborder="0">').attr( 'title', noframe.text() );
+			frame = $( '<iframe id="wp-auth-check-frame" frameborder="0">' ).attr( 'title', noframe.text() );
 			frame.on( 'load', function() {
 				var height, body;
 
@@ -35,10 +36,10 @@
 				form.removeClass( 'loading' );
 
 				try {
-					body = $(this).contents().find('body');
+					body = $( this ).contents().find( 'body' );
 					height = body.height();
-				} catch(e) {
-					wrap.addClass('fallback');
+				} catch( er ) {
+					wrap.addClass( 'fallback' );
 					parent.css( 'max-height', '' );
 					form.remove();
 					noframe.focus();
@@ -46,34 +47,37 @@
 				}
 
 				if ( height ) {
-					if ( body && body.hasClass('interim-login-success') )
+					if ( body && body.hasClass( 'interim-login-success' ) ) {
 						hide();
-					else
+					} else {
 						parent.css( 'max-height', height + 40 + 'px' );
+					}
 				} else if ( ! body || ! body.length ) {
-					// Catch "silent" iframe origin exceptions in WebKit after another page is
-					// loaded in the iframe.
-					wrap.addClass('fallback');
+					// Catch "silent" iframe origin exceptions in WebKit
+					// after another page is loaded in the iframe.
+					wrap.addClass( 'fallback' );
 					parent.css( 'max-height', '' );
 					form.remove();
 					noframe.focus();
 				}
-			}).attr( 'src', form.data('src') );
+			}).attr( 'src', form.data( 'src' ) );
 
 			form.append( frame );
 		}
 
 		$( 'body' ).addClass( 'modal-open' );
-		wrap.removeClass('hidden');
+		wrap.removeClass( 'hidden' );
 
 		if ( frame ) {
 			frame.focus();
-			// WebKit doesn't throw an error if the iframe fails to load because of
-			// "X-Frame-Options: DENY" header.
-			// Wait for 10 sec. and switch to the fallback text.
+			/*
+			 * WebKit doesn't throw an error if the iframe fails to load
+			 * because of "X-Frame-Options: DENY" header.
+			 * Wait for 10 seconds and switch to the fallback text.
+			 */
 			setTimeout( function() {
 				if ( ! loaded ) {
-					wrap.addClass('fallback');
+					wrap.addClass( 'fallback' );
 					form.remove();
 					noframe.focus();
 				}
@@ -90,34 +94,40 @@
 	 * @private
 	 */
 	function hide() {
-		$(window).off( 'beforeunload.wp-auth-check' );
+		var adminpage = window.adminpage,
+			wp        = window.wp;
 
-		// When on the Edit Post screen, speed up heartbeat after the user logs in to
-		// quickly refresh nonces.
-		if ( typeof adminpage !== 'undefined' && ( adminpage === 'post-php' || adminpage === 'post-new-php' ) &&
-			typeof wp !== 'undefined' && wp.heartbeat ) {
+		$( window ).off( 'beforeunload.wp-auth-check' );
 
-			$(document).off( 'heartbeat-tick.wp-auth-check' );
+		// When on the Edit Post screen, speed up heartbeat
+		// after the user logs in to quickly refresh nonces.
+		if ( ( adminpage === 'post-php' || adminpage === 'post-new-php' ) && wp && wp.heartbeat ) {
 			wp.heartbeat.connectNow();
 		}
 
 		wrap.fadeOut( 200, function() {
-			wrap.addClass('hidden').css('display', '');
-			$('#wp-auth-check-frame').remove();
+			wrap.addClass( 'hidden' ).css( 'display', '' );
+			$( '#wp-auth-check-frame' ).remove();
 			$( 'body' ).removeClass( 'modal-open' );
 		});
 	}
 
 	/**
-	 * Schedules when the next time the authentication check will be done.
+	 * Set or reset the tempHidden variable used to pause showing of the modal
+	 * after a user closes it without logging in.
 	 *
-	 * @since 3.6.0
+	 * @since 5.5.0
 	 * @private
 	 */
-	function schedule() {
-		// In seconds, default 3 min.
-		var interval = parseInt( window.authcheckL10n.interval, 10 ) || 180;
-		next = ( new Date() ).getTime() + ( interval * 1000 );
+	function setShowTimeout() {
+		tempHidden = true;
+		window.clearTimeout( tempHiddenTimeout );
+		tempHiddenTimeout = window.setTimeout(
+			function() {
+				tempHidden = false;
+			},
+			300000 // 5 min.
+		);
 	}
 
 	/**
@@ -136,31 +146,13 @@
 	 */
 	$( document ).on( 'heartbeat-tick.wp-auth-check', function( e, data ) {
 		if ( 'wp-auth-check' in data ) {
-			schedule();
-			if ( ! data['wp-auth-check'] && wrap.hasClass('hidden') ) {
+			if ( ! data['wp-auth-check'] && wrap.hasClass( 'hidden' ) && ! tempHidden ) {
 				show();
-			} else if ( data['wp-auth-check'] && ! wrap.hasClass('hidden') ) {
+			} else if ( data['wp-auth-check'] && ! wrap.hasClass( 'hidden' ) ) {
 				hide();
 			}
 		}
-
-	/**
-	 * Binds to the Heartbeat Send event.
-	 *
-	 * @ignore
-	 *
-	 * @since 3.6.0
-	 *
-	 * @param {Object} e The heartbeat-send event that has been triggered.
-	 * @param {Object} data Response data.
-	 */
-	}).on( 'heartbeat-send.wp-auth-check', function( e, data ) {
-		if ( ( new Date() ).getTime() > next ) {
-			data['wp-auth-check'] = true;
-		}
-
 	}).ready( function() {
-		schedule();
 
 		/**
 		 * Hides the authentication form popup when the close icon is clicked.
@@ -169,9 +161,10 @@
 		 *
 		 * @since 3.6.0
 		 */
-		wrap = $('#wp-auth-check-wrap');
-		wrap.find('.wp-auth-check-close').on( 'click', function() {
+		wrap = $( '#wp-auth-check-wrap' );
+		wrap.find( '.wp-auth-check-close' ).on( 'click', function() {
 			hide();
+			setShowTimeout();
 		});
 	});