Constant WITNESS_COMMITMENT_HASH_LENGTH 

pub const WITNESS_COMMITMENT_HASH_LENGTH: usize = 32; // 32usize

Witness commitment hash length (BIP141)

The witness commitment in the coinbase transaction contains:

• OP_RETURN (0x6a): 1 byte
• Push opcode (0x24): 1 byte
• Commitment hash: 32 bytes Total: 34 bytes

Reference: BIP141 - Witness commitment format