I understand the position "RTFM First", but that's the actual problem of all configurations: you're reading the config, you're don't understand what the options actually does, you're going to google (nobody reads the docs) to find the answer or to ML to ask the same question again. Name should reflect the behaviour clearly. "Fail" is good for Erlang since "Let it crash!", but CouchDB wouldn't actually "fail" because of empty client certificate: it will just reject such requests and keep going. So actually there are two names that are suitable for configuration: `require_peer_cert` and `reject_if_no_peer_cert`. Last one too verbose.

I understand the reasons why you picked such name, but I feel that it could be better. Or at least comment should clarify what the "fail" actually stands for. Probably, we could ask others devs opinion?