/usr/lib/libsidlstub_f77.so is in libsidl-dev 1.4.0.dfsg-8.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libsidlstub_f77-1.4.0.so
/usr/lib/libsidlstub_f77-1.4.0.so