I think the guest extension is currently not visible on Extiverse, but there was some information in the public README file.
Basically I made it for a client and they licensed it to a few other forums as well, but ultimately it's their call. If the extension appears back on Extiverse I can share the link.
The reason we went this route instead of me publishing the extension directly is because it's specific to a set of compatible extension and it can easily break if any other extension is added. So there's a high chance of additional development time needed if any extension gets added, so I would be unable to support it as a premium extension as it would have to become compatible with a vast majority of community extensions to be useful.
