/usr/share/psychtoolbox-3/PsychSignal/ 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/PsychSignal/ATand2.m
/usr/share/psychtoolbox-3/PsychSignal/ATand360.m
/usr/share/psychtoolbox-3/PsychSignal/AllAll.m
/usr/share/psychtoolbox-3/PsychSignal/AltRound.m
/usr/share/psychtoolbox-3/PsychSignal/AnyAll.m
/usr/share/psychtoolbox-3/PsychSignal/Bandpass.m
/usr/share/psychtoolbox-3/PsychSignal/Bandpass2.m
/usr/share/psychtoolbox-3/PsychSignal/BoolFromSNR.m
/usr/share/psychtoolbox-3/PsychSignal/Contents.m
/usr/share/psychtoolbox-3/PsychSignal/Expand.m
/usr/share/psychtoolbox-3/PsychSignal/HalfRect.m
/usr/share/psychtoolbox-3/PsychSignal/MatMax.m
/usr/share/psychtoolbox-3/PsychSignal/MatMin.m
/usr/share/psychtoolbox-3/PsychSignal/MatMinMax.m
/usr/share/psychtoolbox-3/PsychSignal/MaxAll.m
/usr/share/psychtoolbox-3/PsychSignal/MaxInd.m
/usr/share/psychtoolbox-3/PsychSignal/MeanAll.m
/usr/share/psychtoolbox-3/PsychSignal/MinAll.m
/usr/share/psychtoolbox-3/PsychSignal/MinInd.m
/usr/share/psychtoolbox-3/PsychSignal/OrientationBandpass.m
/usr/share/psychtoolbox-3/PsychSignal/Scale.m
/usr/share/psychtoolbox-3/PsychSignal/StdAll.m
/usr/share/psychtoolbox-3/PsychSignal/SumAll.m
/usr/share/psychtoolbox-3/PsychSignal/Trunc.m