Curse updater - couple of questions

[eomer]

1. I just wanted to ask how it (or WoWInterface updater) checks if addon is up to date? Will any of them recognize newer version of addon if I updated it manually and there is no update on site, or will it replace it with newest version avaiable on the site?
2. Why is curse updater re-installing addons or modules of addons I manually deleted? For example, I don't need Dominos XP and Buff modules and I delete them, but after each run of Curse updater they are here again. Can I stop it from doing this?
3. Is there a way for it to show which addons have updated version?