When you add a group to $wgRestrictionLevels or a permission to $wgRestrictionTypes, it will show a broken message at the protection screen (<protect-level-foo>) because there's no interface translation message for that group/permission. The software should generate one or assume one is there with default filler text, like "[Group]s only" and "[Permission]".
Version: 1.10.x
Severity: minor
URL: http://lists.wikimedia.org/pipermail/mediawiki-l/2007-August/022463.html