But they don't, here's a random block from mempool.space. More than one adresses in the coinbase.
One thing I never understood about nostr:npub18d4r6wanxkyrdfjdrjqzj2ukua5cas669ew2g5w7lf4a8te7awzqey6lt3, Blockstream, and other block explorers is why they show a single address as the “coinbase address”.
A coinbase tx is like any other in that it can spend to many addresses.
Discussion
Gotcha. I guess I was thinking of their API, which returns a field called “coinbase_address” which I believe only ever has 1 address.