Constant ring::signature::MAX_LEN

pub(crate) const MAX_LEN: usize = _; // 105usize

The longest signature is an ASN.1 P-384 signature where r and s are of maximum length with the leading high bit set on each. Then each component will have a tag, a one-byte length, and a one-byte “I’m not negative” prefix, and the outer sequence will have a two-byte length.