Run multiple executables alongside each other within the same proton wineprefix.
Useful for widescreen fixes, trainers, etc.

Documentation

gitlab https://gitlab.com/xaryphon/protonhax

Install

pacaur -S protonhax  # archlinux

Within steam, configure game to launch using protonhax.

rclick game:
  - properties
    - # ... launch commands ?
protonhax init %COMMAND%

protonhax ls  # list apps that are running
protonhax run ${APPID} ${EXE} ${ARGS..}
protonhax cmd ${APPID}