I just noticed a change in the font used on JS pages such as
https://pt.wikipedia.org/wiki/MediaWiki:Common.js?action=edit&debug=1
https://fr.wikipedia.org/wiki/MediaWiki:Common.js?action=edit&debug=1
They are using "font-family: sans-serif" instead of the desired "font-family: monospace". It is still possible to see the old behavior on e.g.
https://en.wikipedia.org/wiki/MediaWiki:Common.js?action=edit&debug=1
The three wikis above are running 1.22wmf15 (5241654) right now, and all of them have CodeEditor installed.
I tested using Google Chrome 29.0.1547.65 and Firefox 23.0.
Version: unspecified
Severity: normal