sbool domainIsUnder_extended(S domain, S mainDomain) {
  new Matches m;
  if (startsWith(mainDomain, "@.", m))
    ret eqic(domain, m.rest());
  if (startsWith(mainDomain, "*.", m))
    ret ewic(domain, "." + mainDomain);
  ret domainIsUnder(domain, mainDomain);
}