Wikimedia Bugzilla is closed!

First, the red warning text that appears in some places (like the edit preview)
should always be properly done with CSS. (Aside from simple correctness, see
feature request [[989]] for a reason.) I'll suggest <class = "warning">.

But this only works in system text. Red warning text is also used in wiki-edited
text (see the top of [[w:en:Donations for victims of the 2004 Indian Ocean
earthquake]] for an example). So we should have a wiki markup for it. I'll
suggest "<warn>...</warn>", and if anybody objects to that on the grounds that
wiki tags shouldn't look like HTML tags (as <nowiki> does), then I'll let them
suggest an alternative ^_^.