bookreader I think its obvious that somebody would have to maintain those servers.
I suspect anybody who has the skills to set up the infrastructure and the funding to pay for the server(s) can also build GrapheneOS from source and change the built-in server selectors to the desired values. Signing the builds would mean that if, hypothetically, the GrapheneOS project were compromised, the devices running the custom build would get only system images built and signed by the entity doing the builds and signing, not the hypothetically compromised project.
bookreader Basically what is being asked for isn't just "google"/"grapheneos"/"disabled", but rather also add a "custom" option. From the top of my head, connectivity check, gps, updater.
That could be done, and it's possible that a pull request implementing that would be accepted. But the situation is not like the situation for a custom DNS resolver, where there are tens or hundreds of candidates that GrapheneOS users might wish to select among. At present there are not many SUPL proxies (maybe just Google's and GrapheneOS's?), and at present there is one GrapheneOS system image update server.
Meanwhile, if it is possible for users to plug in arbitrary values, some will plug in a wrong value, raising the support load. As long as there is only one "right answer" for 99.9% of users, a situation in which the 0.1% select a custom server by doing a build might be the right tradeoff for the project team.
Please note that I do not speak for the GrapheneOS project.