http://rk56xqf2fwp76cl4cwbarmsnn5nveqrurmvn7ek2yeqez52nq7awb2qd.onion/index.php?title=.onion&action=edit
They are 16 characters long for V2 onion services and 56 characters long for V3 onion services. These strings can be made up of any letter of the alphabet, and decimal digits from 2 to 7, representing in base32 either an 80-bit hash ("version 2", or 16-character) or a 256-bit ed25519 public key along with a version number and a checksum of the key and version number ("version 3", "next gen", or 56-character).