/usr/lib/puredata/doc/1.manual is in puredata-doc 0.48.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/puredata/doc/../../../share/puredata/doc/1.manual
/usr/lib/puredata/doc/../../../share/puredata/doc/1.manual