Example code is at https://github.com/Tevemadar/Collab.PHP , and a single-page version of the text is also available there..

What can I find here?

• Very short collab app example (host, register, use)
• Barely longer example about dealing with OIDC stuff
• The hosted examples themselves.

The token exchange happens in PHP code (it's "curl-like"), everything else is browser-side.

Who has access?

Anyone "has access", but developers can really make use of it.