This is the official YOURLS .pot file to generate and maintain your own translations.

To create translation files:

1. Download the translation file template YOURLS.pot
2. Rename it to [your-locale].po, where [your-locale] is typically language code, underscore, country code (for instance in Portugal that would be pt_PT, while in Brazil it’d be pt_BR).
3. Install a translation software: it’s nothing more than a text editor capable of reading .po files, showing you the untranslated string and a text box where you type in the translation, and saving a .mo file which is what PHP needs. A cross platform, simple yet complete editor is Poedit.
4. Translate all the strings. You'll have a fully translated pt_BR.po and the generated pt_BR.mo

To check your translation file and load it in YOURLS:

1. Download a nightly build or update via SVN. Read this
2. Drop your pt_BR.po and pt_BR.mo files in user/languages
3. Add define( 'YOURLS_LANG', 'pt_BR' ) to your config.php
4. That’s it! Play with YOURLS to check everything is fine

For more details, tips and screenshots, see the related blog post

When the YOURLS.pot template file is updated with new or modified strings to translate, you don't have to start over your translation file.

1. Download the translation file template YOURLS.pot
2. Put it in the same directory as your translation file, eg pt_BR.po
3. In Poedit select Catalogue then Update from POT file. Now translate only the new strings.

When your translation file is all fine, make sure others can benefit from you hard work!

1. Upload your two PO and MO files somewhere on the interweb.
   It's best to use a source control service, such as Google Code or Github: this will make your changes easy to track, your files easy to maintain, and others' contributions easy to implement. If you don’t want to use SVN or Git, a regular hosting (your blog) will be OK
2. Make it clear for users: a directory with clearly labelled files (yourls-1.6-pt_BR.zip for instance) so they know what to pick.
3. Ping us! Open a new issue here and tell us where your translation lives so we can add it to the list of available languages

See http://yourls.org/translations

LeoColomb - L10n was a low priority feature but he threw his patch at my face :)

Do whatever the hell you want with it.