[TheRealSteel]

I agree it's very annoying you can't change keyboard shortcuts in Firefox.

If you use the Mac trackpad, use BetterTouchTool to assign a gesture (I use tiptap left and tiptap right) to the switch tabs left and switch tabs right keyboard shortcuts. You can assign them per-app so it can send a different combo for Firefox than anything else.

[timewarrior]

As mentioned in the original post, I don’t want to install additional software. If I was open to that Karabiner would be perfect. Thanks!