/usr/lib/x86_64-linux-gnu/libSoQt.so is in libsoqt4-dev 1.6.0~e8310f-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libSoQt.so.20.6.0
/usr/lib/x86_64-linux-gnu/libSoQt.so.20.6.0