Support level 5 shift modifier?

[madsmtm]

I found this in the source for the SDL, haven't heard about it before, but apparently XKB has the concept of a "level 5 shift", a good explanation is in here.

Is this something that makes sense for keyboard-types to support? And if so, how?

[pyfisch]

Is this Level 5 Shift supported by any contemporary keyboard?

Lets keep this issue open, if you want to use Level 5 Shift in your application I am happy to find a way to add it to this crate.