Constant ed25519_dalek_blake2b::EXPANDED_SECRET_KEY_LENGTH

pub const EXPANDED_SECRET_KEY_LENGTH: usize = EXPANDED_SECRET_KEY_KEY_LENGTH + EXPANDED_SECRET_KEY_NONCE_LENGTH; // 0x0_000_000_000_000_040usize

The length of an "expanded" ed25519 key, ExpandedSecretKey, in bytes.