2012-05-01: Support was added for Waymarked Trails. (Other news...)
Changing Japanese namespace names of MediaWiki
Fragment of a discussion from Support
Just review all MediaWiki core translations and look them up. That's probably the most elaborate way, as I expect there is more than one occurrence. Btw, the changes have been deployed as far as I know.
MediaWiki:Talk/ja, MediaWiki:Talkpagelinktext/ja, MediaWiki:Vector-namespace-talk/ja have been changed. Other messages?
You should check all messages containing namespace names as text. Messages like nstab-category ("Category") and the ones for other namespaces.
Now no message contains "ノート" in MediaWiki core, except exif-makernote ("<exif-makernote>").
But "ノート" is still used on page tab label (c.f. [1]). Why?