cat /var/log/Xorg.0.log | grep -i glx
(II) LoadModule: "glx"
(II) Loading /usr/lib/xorg/modules/extensions/libglx.so
(II) Module glx: vendor="NVIDIA Corporation"
(II) Loading extension GLX
(**) NVIDIA(0): Option "AllowGLXWithComposite" "true"
(**) NVIDIA(0): Option "AddARGBGLXVisuals" "True"
(II) NVIDIA(0): Support for GLX with the Damage and Composite X extensions is
(II) Loading extension NV-GLX
(II) Initializing extension GLX