[drMerry]

so here is a version I made myself with filetype extension finding support inside epubs.
I used it to search on: db, store

and found a lot of files.
Mind you, it is very verbose, just to test

THIS IS NO OFFICIAL RELEASE.
NO GUARANTEE, NO SUPPORT (AND KIWIDUDE HAS HAD NO HAND IN THIS RELEASE, SO DON'T BLAME HIM FOR ERRORS)

I did not see the quality check threat so started a new one.
While this is not a release by kiwidude, and I'm not usually programming in python, I moved it here.
This version is a little less verbose than the version I put in the original post.
It is also somewhat faster because I did put som code outside the loop.