Why do ed25519 signature verify functions accept 96-byte signatures? Take this piece of code for one example:
crypto_sign_ed25519_open() requires that signatures be at least 64 bytes (512 bits) but will accept longer ones, and
get_hram() will include extra bytes at the end of the signature in its hashing step if they are present. Yet
crypto_sign_ed25519() generates a 64-byte signature.
Is this some kind of legacy thing? Does it have any cryptographic implication?