When I write in French I use Bépo layout (like dvorak for french language)

$ setxkbmap -query
rules: evdev
model: pc105
layout: fr
variant: bepo

How can I display "fr (bepo)" in my polybar?

I can see there's 3 variables in the module/xkeyboard.cpp:
%name%
%layout%
%number%

Is it possible to add the variant variable?

Regards