Hello @barfin, Steam injects the steam overlay into games by LD_PRELOAD'ing a 32 bit and 64 bit variant of gameoverlayrenderer.so when launching the game. One will silently load while the other harmlessly fails. They can be found at <Steam install dir>/ubuntu12_{32,64}/gameoverlayrenderer.so.
You can try to do similar when running games outside of Steam, but if anything breaks, you get to keep the pieces.
Closing because this is a feature request for integration outside of the Steam client and not for the Steam client itself. This should be pondered by the external project that would potentially benefit from it.
Nothing extracted yet.
Your system information
something like this
"$ STEAM_OVERLAY=1 ~/gamedir/game"
after launching game it should have steam overlay on it without adding that non-steam game to steam library or launching in steam library
it would be such a great feature and it will be super useful to use in lutris