It did not occur to me from the documentation that --change-host-header’s equivalent was header_up Host {upstream_hostport}, especially as the respective settings are described in completely different sections of the documentation and not linked with each other.
If the docs have a git repo, I’m happy to provide a PR for it!
Well, if you’re looking to use the reverse_proxy directive, you should look at its docs as authoritative
The command-line interface and Caddyfile aren’t related. They’re two distinct ways of using Caddy, not connected to eachother. Their similarity is that they both produce JSON config that Caddy actually runs with.