Jetstream already supports filtering by repository, and in theory we could add a filter here for "repositories that I follow AND posts with a root pointing to a repository that I follow", which would hydrate threads.

That sounds great, but everybody consuming the whole firehose from their browser would scale pretty badly. As far as I can tell the current relay API doesn't support any filtering, so... consuming from Jetstream?

What you are looking at here is the 301 response of Nginx 1.22.1.