Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
extraPopupFilters=[];

function popupFilterWarn(wikiText, download) {
  var article= (new Title()).fromURL(download.url);
  if (!article.userName) {
    return '';
  }
  var talkpage = article.talkPage() || article;
  var html='<a href="http://en.wikipedia.org/w/index.php?title=' + escape(talkpage) + '&action=edit&autoedit=s/$/\\n\\nThanks for experimenting with Wikipedia. Your test worked, and has been reverted or removed. Please use [[Wikipedia:Sandbox|the sandbox]] for any other tests you want to do. Take a look at the [[Wikipedia:Welcome, newcomers|welcome page]] if you would like to learn more about contributing to our encyclopedia. Thanks. <!-- from Template:Test --> %20[[User:Krashlandon|Krashlandon]] [[WP:EA|<font color="green">(e)</font>]] 22:02, 24 February 2006 (UTC)/&autosummary=Your%20edits&autoclick=wpPreview">warn</a>';
  return html;
};

extraPopupFilters.push(popupFilterWarn);