/usr/share/doc/python3-certbot-nginx/html/_static/underscore.js is in python-certbot-nginx-doc 0.23.0-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/python3-certbot-nginx/html/_static/../../../../javascript/sphinxdoc/1.0/underscore.js