/usr/bin/WPrefs is in wmaker 0.95.0+20111028-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/GNUstep/System/Applications/WPrefs.app/WPrefs
/usr/bin/../lib/GNUstep/System/Applications/WPrefs.app/WPrefs