update:
- a repo used for older v0.2.x versions no longer exists, but the necessary packages were moved to other repo's, i modified all impacted Dockerfiles, everything builds again
Wouldn't it make more sense for you to simply fork the repositories to your own github account instead of pointing it to someone else's?
Github has seemingly unlimited file storage, and short of a DMCA takedown, the files aren't going anywhere.[/list]
Those are package repo's (not github repo's), some of them are Gb's of (binary) rpm packages, sometimes even providing regular patches. I'm not sure github would approve if i cloned those into a github repo

For github repo's, you do have a valid point, i should probably fork those, so i'm not longer depending on repo's that might be removed in the future. I'll put that one on my to-do list.