Names of notification themes (Bright, Default, Smoke and Retro, all expect ZOMG-PONIES!) should be translateable as terminal color profiles are. That's all :D
It actually belongs to Notifications config dialog.
While this is doable (by introducing metadata files for notifyd themes) I'm not sure this is worth the effort. The gain would also be very little because those are only *names* and they may not even mean anything in someone's native language (ZOMG-PONIES! is a great example).
I think for now I won't go the extra mile for theme names.