The list of mastodon instances runs a software found in a GitHub project but the database itself is centralized on https://instances.social/. As a result, if I was to run my own list of mastodon instances, would need to use the API to get the list from https://instances.social/ and start from there. And any I would need updates from that list too… and if someone updates the list on my server, I’d like to notify instances.social about it. It looks like both my instance and https://instances.social/ would benefit from being federated.
I think it would make sense to design fedeproxy to not be centralized in this way.