How do modifiers work (USB HID)?

[jamadagni (Shriramana Sharma)]

@jesse

I’ve never heard of a host-side…anything that behaves differently with “Left Control-X” vs “Right Control-X” or “Left Shift X” vs “Right Shift X”. The same is not true of Alt, which is why it gets two bits.

In XKB, RCtrl is the default fifth level modifier. Is there a way to specifically select this as available for RAlt?

(This topic was linked to from my recent thread.)