/usr/lib/pd/extra/purepd/LICENSE.txt is in pd-purepd 0.1.1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/pd/extra/purepd/../../../../share/common-licenses/GPL-2
/usr/lib/pd/extra/purepd/../../../../share/common-licenses/GPL-2