http://jptvwdeyknkv6oiwjtr2kxzehfnmcujl7rf7vytaikmwlvze773uiyyd.onion?page=46
While v2 onion addresses are just a hash and therefore all combinations of
16 base32 characters are valid addresses, this isn't true for v3 onion
addresses. Put simply, a v3 onion address is (1) a 32-byte (not bit) public
key, (2) a checksum, and (3) a version all encoded together (in that order) in
base32. The version is always 3 (or 'd' in base32), thus they always end in
'd'.