We should ensure that AP URLs can contain port numbers. I believe this is the single most helpful thing that we can provide to people experimenting with server software.
At present, some clients restrict port numbers to 443, sometimes trying 80 first. A person can install any package they like, but to test it they need both root access and a separate publicly-visible hostname and IP address which isn’t already running a web service. This can be a tall order.
This may be the case for some servers too— I don’t know. But I think everyone should check their code, client or server, to ensure that port numbers work.
This also applies to custom protocols such as Mastodon!
(Possible #hackathon topic?)