Bugzilla used to be written in Tcl. It got rewritten in Perl because they recognized that it would be easier to get people to contribute to it if they did. For the same reasons, the same thing should happen again; today, the fact that it's written in Perl is a liability in much the same way that it was a strength circa Y2K.

I love Bugzilla, and it'd be great if everyone would drop out of the mass psychosis that GitHub issues (and the culture that has developed there) represents anything close to the correct or optimal way to manage bugs. I can't, however, actually expect or recommend with a straight face that anyone deploy or work on it, considering it's a foreign codebase written in Perl, so it's not something I want to do myself, either.