bad news but your answer is very important for the future of all plugins.
If sombody developed a module which runs fine with Moodle 2.0, 2.1, 2.2, and 2.3 but he marked it only for MOODLE_20_STABLE then nobody can get the translation for Moodle 2.2 or 2.3.
First, the mrbs block got the last change on 20120308 and it works with all Moodle 2.x versions.
Second, the lightbox gallery was fixed at least on 20120309. It's very nice with Moodle 2.1, 2.2, and 2.3 but nobody will use the module without a proper translation.
Third, the hotpot module can be used and can be translated in all branches. Does this module exist in a correct form ... it seems so. Where is the difference? Hotpot works with Moodle 2.x .... I can get a zip file without any branch. I have to download the hotpot module from http://bateson.kanazawa-gu.ac.jp/moodle/zip/moodle-2.x.hotpot-module.zip
Fourth, I found the book module with different branches on the server https://github.com/skodak/moodle-mod_book and it has a translation in all branches. Is this the correct way to get into the translation tool?
What do you think about the four different modules and the four different ways?
Moodle Partner - moodleSCHULE e.V.