The list is here https://docs.mesa3d.org/envvars.html (and somewhere in Mesa sources I presume). Some are I've used or found otherwise useful.
LIVVA_DRIVER_NAME=foo
overrides vaapi default driver. Here, given foo, the driver file would befoo_drv_video.so
MESA_LOADER_DRIVER_OVERRIDE=foo
overrides a graphics driver binary. Givenfoo
, the driver file would befoo_dri.so
LD_LIBRARY_PATH=/full/path/to/mesa-repo-root-dir/lib LIBGL_DRIVERS_PATH=/full/path/to/mesa-repo-root-dir/lib/gallium app
an outdated example of running an app with the built Mesa instead of the system one. "Outdated" because the paths are for pre-meson Mesa. Nowadays the paths are changed, gotta test it.