Use capslock as an additional modifier key

Feature Description:

I would like to use capslock as an additional modifier key.

In vscode I do this by making capslock an "additional hyper" (in the kde settings, I am on Linux). Then, I can bind meta+<key> to a command (so actually the windows key and capslock are then the same). This is my xmodmap output

shift       Shift_L (0x32),  Shift_R (0x3e)
lock      
control     Control_L (0x25),  Control_R (0x69)
mod1        Alt_L (0x40),  Meta_L (0xcd)
mod2        Num_Lock (0x4d)
mod3      
mod4        Hyper_L (0x42),  Super_L (0x85),  Super_R (0x86),  Super_L (0xce),  Hyper_L (0xcf)
mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb)

Not sure if possible to do this in the browser (I am using theia via gitpod).