I have created a GitHub repo storing several Firefox extension utility scripts that I wrote. Here's the rundown on what this repository contains:

compareLocales.pl

Compares all of the locales it finds against a "master" locale (en-US by default) and reports the number of exact duplicate entries for each. This is useful for figuring out which locales have not been updated.

entityToProperty.pl

Converts a given list of locale entities into corresponding properties. Handy for migrating existing entity localizations into a .properties file.

removeLocaleEntries.pl

This script removes a given list of entries from all of the locale folders it finds in the current working directory and below. Useful for cleaning up strings that are no longer needed.

Hopefully others will find these scripts to be useful. I hope to add additional scripts to this repository over time.