RFB Protocol Security for VNC Client Implementation

I’m exploring the RFB protocol used by VNC connections on macOS. In the initial part of the handshake, as described in the spec, the server returns a list of security types it supports. Connecting to my iMac running macOS 10.15.6, I get the following list: 30, 33, 36, 35. Looking at the IANA registrations for this protocol, 30-35 are assigned to Apple, and 36 is “Unassigned.”

Are there any publicly-available resources to understand the security implementation of the built-in VNC server on macOS? I see a blog post about it from 2011 (I can’t add the link here for some reason), but nothing newer and I suspect the authentication methods have improved since then.
RFB Protocol Security for VNC Client Implementation
 
 
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