On [en] wiktionary, there is an xslt file (for use with the xslt option of the api) called [[wikt:mediawiki:extractFirst.xsl]]. Since the software update, it appears that pages in the mediawiki and mediwiki talk namespace have their first letter case insensitive, even on wikis where normal pages can begin with a lowercase letter.
Thus it is now impossible to access [[wikt:mediawiki:extractFirst.xsl]] as it gets converted to [[wikt:mediawiki:ExtractFirst.xsl]] (Which does not exist).
Version: unspecified
Severity: critical
URL: http://en.wiktionary.org/wiki/MediaWiki_talk:extractFirst.xsl