A webservice with three different components to aid in proper documentation ordering:

1. An HTTP API that serves JSON pointing to the various different versions of documentation available and its URLs.
2. A dynamically generated Nginx file that maps URLs to the proper (current) versions of a project(s) documentation.
3. A JavaScript library that should be injected into the Sphinx theme that understands how to talk to the exposed HTTP API and display a navigation menu to move to different documentation versions.

From wikipedia:

"Ayni (Quechua, also spelled Ayniy or Aini) is a traditional form of mutual help practiced in indigenous communities (ayllu) in the Andes. Ayni means proper relationship. Member of a community help another member for private purposes when support is needed, e.g. in house construction or agricultural works."

Ayni is here to help documentation help others, by properly organizing it and showing the right path to the correct doc destination.