The opens a new perspective that I did not think about up-to-now. Thank You!
Actually I thought about something simpler, eg I want to return to the exact same project state before the start of the sprint planning if something goes wrong during the sprint planning.
In my naive approach I would export the project into the XML file, would add and commit it to a git repository with a meaningful comment,on the command line and then if something goes wrong import it again.
So I ask now: Are there a kind of convenient functions which support this kind of work?