/usr/share/doc/postgresql-9.5-pgrouting-doc/html/en/_static/underscore.js is in postgresql-9.5-pgrouting-doc 2.1.0-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/postgresql-9.5-pgrouting-doc/html/en/_static/../../../../../javascript/sphinxdoc/1.0/underscore.js