mod_http_oauth2: Validate consistency of response and grant types Ensure that these correlated fields make sense per RFC 7591 § 2.1, even though we currently only check the response type during authorization. This could probably all be deleted if (when!) we remove the implicit grant, since then these things don't make any sense anymore.

Introduction
============

This module checks the IP address of newly registered users against a
DNS block list. If a positive match is found, it gets logged.

Configuration
=============

  Option              Type     Default
  ------------------- -------- ------------
  registration\_rbl   string   *Required*