Metaplex Token Metadata

The Metaplex Token Metadata program (metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s) that attaches rich metadata to any SPL token or NFT. It creates a PDA-derived metadata account storing: name, symbol, URI (pointing to off-chain JSON), creators array, seller fee basis points, and collection info. The de facto standard for NFT metadata on Solana.