/usr/lib/x86_64-linux-gnu/libecpg_compat.so is in libecpg-dev 9.4.18-0+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libecpg_compat.so.3.6
/usr/lib/x86_64-linux-gnu/libecpg_compat.so.3.6