-# is allowed. If the Publickey is used it includes the file path to the
-# public key file. If none of them is provided then authentication is not
-# required. The PublicKey can be set multiple times to set multiple
-# public keys for one connection.
+# is allowed. The "PublicKey" includes the single key contained in the
+# specified file, while "PublicKeyDir" includes all files in the specified
+# directory, which must all be valid public keys with ".pub" suffix.