/usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0 is in libsdl2-2.0-0 2.0.5+dfsg1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.4.1
/usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.4.1