The list of TCP and UDP port numbers [1] is a treasure trove of historical artefacts. It's amazingly hard to find information on e.g. "compressnet", which is wasting port 2 and port 3 for eternity.
I was skeptical at first but found evidence to corroborate it's the same thing, the key fact being the company named Process Software.
The reference in RFC1340 for it says "Bernie Volz" of process.com. Searching on that let me to a Web-0.9 style page with the text "compressnet/tcp is a protocol that is used to compress TCP connections for WANS. It used two ports to compress tcp conections, one to send the compressed TCP connection data through, and one used for the management of CompressNet. This is a commercial product only."
[1] https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbe...