Around November 2023 Bluesky moved users off the single bsky.social PDS onto 10 separate servers — all run by Bluesky but named after mushrooms (e.g. Amanita, the red-and-white spotted one) as an early federation test. Each mushroom PDS holds hundreds of thousands of SQLite files (one per account). Kuba was originally on Amanita before moving to his own independent PDS a year later.