/usr/lib/x86_64-linux-gnu/dri/nouveau_drv_video.so is in mesa-va-drivers 11.2.0-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/dri/gallium_drv_video.so
/usr/lib/x86_64-linux-gnu/dri/gallium_drv_video.so