https://www.hcomo.it/core/misc/announce.js?v=9.4.8

1/**
2* DO NOT EDIT THIS FILE.
3* See the following change record for more information,
4* https://www.drupal.org/node/2815083
5* @preserve
6**/
7
8(function (Drupal, debounce) {
9  var liveElement;
10  var announcements = [];
11  Drupal.behaviors.drupalAnnounce = {
12    attach: function attach(context) {
13      if (!liveElement) {
14        liveElement = document.createElement('div');
15        liveElement.id = 'drupal-live-announce';
16        liveElement.className = 'visually-hidden';
17        liveElement.setAttribute('aria-live', 'polite');
18        liveElement.setAttribute('aria-busy', 'false');
19        document.body.appendChild(liveElement);
20      }
21    }
22  };
23
24  function announce() {
25    var text = [];
26    var priority = 'polite';
27    var announcement;
28    var il = announcements.length;
29
30    for (var i = 0; i < il; i++) {
31      announcement = announcements.pop();
32      text.unshift(announcement.text);
33
34      if (announcement.priority === 'assertive') {
35        priority = 'assertive';
36      }
37    }
38
39    if (text.length) {
40      liveElement.innerHTML = '';
41      liveElement.setAttribute('aria-busy', 'true');
42      liveElement.setAttribute('aria-live', priority);
43      liveElement.innerHTML = text.join('\n');
44      liveElement.setAttribute('aria-busy', 'false');
45    }
46  }
47
48  Drupal.announce = function (text, priority) {
49    announcements.push({
50      text: text,
51      priority: priority
52    });
53    return debounce(announce, 200)();
54  };
55})(Drupal, Drupal.debounce);