I am not quite sure what rules.evdev.lst does, but it certainly gets read by setxkbmap. So to reproduce the bug you may need
$ diff /usr/share/X11/xkb/rules/evdev.lst /usr/local/share/X11/xkb/rules/evdev.lst 659a660 > mod3 gb: Mod3 modifier
which I omitted to mention in my report above.
I am not quite sure what rules.evdev.lst does, but it certainly gets read by setxkbmap. So to reproduce the bug you may need
$ diff /usr/share/ X11/xkb/ rules/evdev. lst /usr/local/ share/X11/ xkb/rules/ evdev.lst
659a660
> mod3 gb: Mod3 modifier
which I omitted to mention in my report above.