mevboost.org has been sunset
mevboost.org was a project by Anish Agnihotri at the transition of Ethereum to Proof-of-Stake. Over its lifetime, it serviced ~30M requests, stored 1.5M payloads across nine relays, and was a leading MEVBoost-adoption tracker.
Excellent alternatives include payload.de, relayscan.io, and mevboost.pics.