/usr/share/doc/gnustep-gui-common/User is in gnustep-gui-doc 0.22.0-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gnustep-gui-common/../../GNUstep/Documentation/User
/usr/share/doc/gnustep-gui-common/../../GNUstep/Documentation/User