/usr/lib/x86_64-linux-gnu/libwx_gtk3u_richtext-3.0.so is in libwxgtk3.0-gtk3-dev 3.0.4+dfsg-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libwx_gtk3u_richtext-3.0.so.0
/usr/lib/x86_64-linux-gnu/libwx_gtk3u_richtext-3.0.so.0