var bugPageURL = 'https://bugs.webkit.org/show_bug.cgi?id=' .. $0;
var bugPageXML = web.xml(bugPageURL);
var s = "";
if (#bugPageXML == 0)
  let s = "Unable to access bug's page. Try reloading this page to see bug's status and summary in this tooltip.";
else{
  let s = xml.text(bugPageXML, '//span[@id="static_bug_status"]');
  if (s){
    // Remove \n and redundant spaces
    let s = string.trimEnd(string.replace(s, "\n", ""));
    if (string.contains(s, "  "))
      let s = string.join(list.select(string.split(s, " "), "#$>0"), " ");
    let s ..= ' - ' .. xml.text(bugPageXML, '//span[@id="short_desc_nonedit_display"]');
  }
  else if (string.contains(bugPageXML, "Access Denied"))
    let s = "The access to the bug's page is restricted.";
}

<a rel="external" href=(bugPageURL) class="external" title=(s)>xml.text(localString({en: "WebKit bug ", ca: "WebKit errada ", cs: "WebKit chyba ", pl: "WebKit błąd "})) .. $0</a>;