/usr/lib/x86_64-linux-gnu/libpgm-5.2.so is in libpgm-dev 5.2.122~dfsg-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libpgm-5.2.so.0.0.122
/usr/lib/x86_64-linux-gnu/libpgm-5.2.so.0.0.122