To have Lovely Forks display its magic when viewing GitHub with Firefox Android, I must either select "Desktop version" (if GitHub offers this on a given page) or ask Fennec to "Request desktop site" in its menu.
I don't know if the GitHub mobile site would allow Lovely Forks to work at all or with reasonable modifications to LF's code.
GitHub's mobile site unfortunately hides various useful site features.
Thanks,
Doug