https://mongoid.org redirects to https://mongoid.github.io which is a landing page maintained by the community rather than MongoDB. Maintainers include Daniel Doubrovkine (AWS), Emily Stolfo (Elastic), and Durran Jordan (MongoDB). Currently listed versions include:

• Latest (link back to https://mongoid.org which sporadically displays a TLS warning)
• Mongoid 5 and 6 (link back to https://mongoid.org which sporadically displays a TLS warning)
• Mongoid 4 (link works)
• Mongoid 3 (link works)

This page isn't useful. It leads either back to itself or very outdated documentation. Note that this is the homepage listed in the gem metadata and a likely place for users to end up as a result.