/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/ is in psychtoolbox-3-common 3.0.14.20170103+git6-g605ff5c.dfsg1-1build1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/0001-Disable-triple-buffering-by-default.patch
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/Contents.m
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/.xinitrc
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/0001-modesetting-Add-custom-UDP-Prime-Sync-protocol-for-P.patch
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/0002-modesetting-Add-custom-low-lag-optimizations-for-Psy.patch
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/Readme.txt
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/lightdm.conf
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/modesetting_drv.la
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/optimusproprietary.conf
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/NVidiaOptimus/xorg.conf
/usr/share/psychtoolbox-3/PsychHardware/LinuxDrivers/xf86-video-intel-2-99-917+MKTripleBufferOff.tar.gz