The three help sources

Read from the plugin directly — for a product installed on this same site. The hub calls its PHP and asks for its topics. No URL, no key, never stale.

Local post type — reads published posts of a help post type registered on this site.

Remote feed — fetches a JSON feed over HTTPS, sending your sync key as X-K2S-Help-Key. This is the only option for anything that is not a WordPress plugin on this site, such as a WHMCS module.