^ key on german keyboard doesn't work

I'd like to report an issue with Vimium-FF that I've also had with Vimium-C but since, I've switched to Vimium-FF.
Note that the behavior with Vimium-FF is a bit different.

I have a german keyboard and I'd like to report that the ^ key (top left) doesn't work as expected, while ° does.
For reference, ° is shift + ^ and ^ is tapping the key twice to give the option of writing ^, ê ô ĉ etc.

Everywhere else in Firefox (and my OS) the keys are not miss-mapped and work as expected.

When I add map ° visitPreviousTab and or map <a-w> visitPreviousTab, visitPreviousTab works fine with SHIFT+^ and ALT+W but just using the default ^ keyboard shortcut or even adding map ^ visitPreviousTab double-tapping the ^ key to type an actual ^ does nothing for me.

To Reproduce

Maybe you can replicate by using a German on-screen keyboard?

Browser, OS and Vimium-FF versions

• Browser name: Firefox
• Browser version: 115.0.2
• Vimium C version: 1.67.7 from Mozilla addons store
• OS name and version: Linux 6.4.2-3-MANJARO #1 SMP PREEMPT_DYNAMIC Fri Jul 7 19:19:45 UTC 2023

Start by reproducing the issue in Firefox with a German keyboard or on-screen keyboard, comparing the default ^ shortcut with ° and ALT+W mappings. Trace the keyboard handling entry point and verify that the ^ shortcut works while double-tapping the key can still produce a literal ^ character.