Wikimedia Bugzilla is closed!

Using some UTF-8 input characters like üöäÜÖÄßéèê etc. which are common on foreign language breaks with MediaWiki default UTF-8 output since the Smarty engine uses Latin1 (ISO-8859-1) per default as said on http://www.smarty.net/docsv2/en/language.modifier.escape

So this will yield unwanted behaviour:

  <!--{$foo|esacpe:'htmlall'}-->

having $foo = "FööBar" this will output rubbish. This is fixed by 

  <!--{$foo|esacpe:'htmlall':'UTF-8'}-->

on every escape usage.