Block 0 — mined December 27, 2020

The headline embedded in the coinbase

spectrum.ieee.org 09/Dec/2020 Photonic Quantum Computer Displays ‘Supremacy’ Over Supercomputers.

The choice mirrors the convention Bitcoin set with its own genesis coinbase, which embedded “The Times 03/Jan/2009 Chancellor on brink of second bailout for banks” — a contemporary headline that timestamped the chain's launch and signalled what it was reacting to. Tidecoin reaches for the same gesture, but instead of a 2008-era bank bailout the headline points at a quantum-computing milestone published 18 days before the chain went live.

The output Tidecoin's own daemon can't classify

Block 0's coinbase pays 50 TDC to a single output of the form

OP_PUSHDATA2 0x0382 <898 bytes Falcon-512 public key> OP_CHECKSIG

That is a textbook bare P2PK output, except the public key is 898 bytes (the size of a Falcon-512 key) instead of the 33 or 65 bytes of a Bitcoin ECDSA key. Tidecoin inherits Bitcoin Core's 0.18.3 script/standard.cpp::Solver() verbatim, and that function's pattern matcher requires a single-byte push length:

static bool MatchPayToPubkey(const CScript& script, valtype& pubkey) {
    if (script.size() == CPubKey::PUBLIC_KEY_SIZE + 2 &&
        script[0] == CPubKey::PUBLIC_KEY_SIZE &&    // <- 898 doesn't fit in a byte
        script.back() == OP_CHECKSIG) { ... }

898 doesn't fit in script[0]; an 898-byte push has to use OP_PUSHDATA2, so the comparison never matches. The genesis output, and every other bare-Falcon P2PK output on the chain, falls through to TX_NONSTANDARD in the node's own classifier. prevblock recognises the shape directly and labels it p2pk_falcon.

This is the single most concrete reason this explorer exists. Tidecoin's own daemon has been calling its own genesis block “nonstandard” for every one of the ~2.5 million blocks since launch. prevblock is the first tool in the ecosystem that doesn't.