[NicolaiS]

Slightly related, but mostly for fun:

You can do valid HTTP & SSH on the same port: https://media.ccc.de/v/bornhack2023-56142-sexy-ssh-hacks#t=4... (Without detecting which client connects, it works just like the "valid PNG and ZIP polyglot" trick)

[hddqsb]

In fact the article mentions a tool for this (sslh), but rejects it because it hides the source IP from the HTTP backend (and other reasons).