/usr/share/psychtoolbox-3/PsychContributed/ is in psychtoolbox-3-common 3.0.12.20160126.dfsg1-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/psychtoolbox-3/PsychContributed/52-MyLinuxJoystick.conf
/usr/share/psychtoolbox-3/PsychContributed/ArmArch/
/usr/share/psychtoolbox-3/PsychContributed/AutoBrightness/
/usr/share/psychtoolbox-3/PsychContributed/AutoBrightness/AutoBrightness.applescript
/usr/share/psychtoolbox-3/PsychContributed/AutoBrightness/AutoBrightness.m
/usr/share/psychtoolbox-3/PsychContributed/Contents.m
/usr/share/psychtoolbox-3/PsychContributed/ShowHideWinTaskbarMex.c
/usr/share/psychtoolbox-3/PsychContributed/WinJoystickMex.c
/usr/share/psychtoolbox-3/PsychContributed/linux_blacklist_kinectvideo
/usr/share/psychtoolbox-3/PsychContributed/ple.m
/usr/share/psychtoolbox-3/PsychContributed/read_rle_rgbe.m