/usr/lib/GNUstep/GDLAdaptors-4.9/MySQL.gdladaptor/stamp.make is in libsope1 2.1.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
OLD_GNUSTEP_STAMP_ASTRING = _MySQL4Adaptor-