/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/ is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/Cable to the PR-650.txt
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650close.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650getserialnumber.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650getsyncfreq.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650init.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650measspd.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650measxyz.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650parsespdstr.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650rawspd.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650rawxyz.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650retrievespd.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650serialread.m
/usr/share/psychtoolbox-3/PsychHardware/PR650Toolbox/PR650setsyncfreq.m