This change makes it impossible to compile caddy on basically all go toolchains distributed by non-rolling-release operating systems. The latest AlpineLinux, 3.22, ships 1.24.6, so I guess I will stay on caddy 2.10 for the forseeable future ...

You shouldn't be using the Go toolchain from distros anyway. It's meant to be installed directly. I recommend using https://github.com/udhos/update-golang to automate it.

Yes, I have noticed the latest trend of every application wrapping itself in its own package manager instead of using the one from my distribution. The one you linked claims minimum system intrusion but wants root access to my system. No thank you.

"root access" to copy itself to /usr/local/bin so it's in your PATH obviously. That's not unexpected at all.

To be clear, all it's doing is downloading the Go zip/tar, extracting it in /usr/local/go, then updating the /usr/local/bin/go, and reporting the version to you. That's it. It doesn't touch anything else on your system. It's just a simple convenience bash script to do the same steps Go's install steps in their docs would have you do anyway.

If you have a version of Go superior to Go 1.21, the Go command itself is able to download the version of the compiler needed for your program: https://go.dev/doc/toolchain