Javi started an IMP develop FAQ in github imp wiki:
You are encouraged to add questions and answers (or propose questions if
you don't know the answer).
As a note, one of the things that makes the github wiki quite tolerable
compared to most wikis is that in addition to a nice, but fairly standard
web interface, the whole wiki is a git repo. As a result, you can clone it
and use any editor you want to work on the files offline and then commit
and push the changes when you are done.