dvdauthor unmaintained upstream - where to report bugs?

I recently noticed a bug in dvdauthor, notified the mailing list [4], and got a reply back that the upstream project [1] is most likely not maintained anymore (no activity for 18+ months). There is a fork[2] of the project at github, as well as unofficial Debian releases [3].

My question is: What to do in the case of unmaintained upstream projects? Where do we report bugs, and is it even thinkable for a distro like ubuntu to switch to a fork?

[1] http://dvdauthor.sourceforge.net/
[2] http://github.com/ldo/dvdauthor/tree/master
[3] http://www.joonet.de/dvdauthor/
[4] https://lists.sourceforge.net/lists/listinfo/dvdauthor-users
[5] https://lists.sourceforge.net/lists/listinfo/dvdauthor-developer

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