The code behind this add-on is so simple* that I haven't bothered with creating a Github repository.

To get support, just mail me (see "Support E-mail" at the add-on listing for my address).

* you can view the code at https://robwu.nl/crxviewer/?crx=https%3A%2F%2Faddons.mozilla.org%2Fen-US%2Ffirefox%2Faddon%2Fdisable-ctrl-q-and-cmd-q