Well, it might be that my native language <> English, so explaining, writing and understanding English create a barrier.
All details about the install manifest can be found in the DNN Wiki:
http://www.dotnetnuke.com...es/cat/Manifest.aspx
There is no such thing as an UnInstall interface, like the iUpgradeable interface you have implemented to be used during installation.
As for RTFM: please understand that there might be a gap in time as well as person between the moment of installation and the moment of uninstall. A simple text explaining what to do would help (and prevent).
As for language: a suggestion (request): please implement the standard DNN localization. It would make the module more in line with common DNN module development standards and usable for others not speaking English (and there are a lot of countries that don't).
If you feel unfamiliar or uncomfortable with lcoalization, please ask. We might be of assistance.