This entire post is about Narro's interface, not the files it handles for translation.
I've changed the internationalization engine that Narro uses for its translation from home made to gettext, so now there's a pot file to translate.
For those using l10n.mozilla.org, you'll have to approve the texts again, but this time you can export a po file an send it to me so I can include it in newer versions.
When you export the translation, a compiled file is generated as well besides the export po file and the translation in Narro is activated instantly.
Sadly, the engine I use, Zend_Translate, doesn't care about plurals, but since it's an active project I hope future versions will support plurals. And right now there are a few places that would use plurals, about 10, so it's not a big issue.