/usr/lib/pd/extra/cxc/LICENSE.txt is in pd-cxc 0.5.2-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/pd/extra/cxc/../../../../share/common-licenses/GPL-2
/usr/lib/pd/extra/cxc/../../../../share/common-licenses/GPL-2