P2PK (Pay-to-Public-Key)
The original Bitcoin output script that pays directly to a public key; most of it dates from 2009-2010 and has never moved.
Pay-to-public-key was the first output type in Bitcoin: the locking script contains the full public key followed by OP_CHECKSIG. Early mining rewards, including the blocks attributed to Satoshi, were paid this way. Because the key is in the script, a P2PK output is key-exposed from the moment it is created, and because most of these coins have been dormant for over a decade, they are the set the quantum debate keeps returning to. ByKaranteli keeps a watch set of dormant P2PK outpoints and diffs it against every new UTXO snapshot; a spend from that set triggers an alert, not a conclusion. Dormant coins moving is the one event worth checking first, and it is also the kind of event that has ordinary explanations.