WP LibreJS module provides compatibility with the GNU LibreJS browser plugin.
It adds tags to pages indicating that all JavaScript is GPL v3+. It will only discover JavaScript files as they are loaded by an administrator user, so every time you add new JavaScript links you will have to load a page that have those links, with an administrator user logged in.
Note: you should only install this module if you are sure all JavaScript on your site is in fact GPL v3+ compatible.
WP LibreJS is free software and it gives you freedom!
This plugin is available for download to be used on your WordPress self-hosted installation.