I just wanted to share my current experience with using the Compare tool at the AMOS Stage page. This tool can be effectively used to detect any sort of differences between two branches (versions) of Moodle strings. Now as the 2.3 release is getting closer, you may want to check for differences between 2.2 and 2.3 version, especially for the case when the English strings has modified while the translation has not.
This way, you can easily detect recent extension of module_help strings, for example. These strings now contain a little bit more detailed description of each module and how to use it. They are displayed by the new "Add an activity or resource" in Moodle 2.3.
Thank you for your work on Moodle lang packs!