This enables using a CouchDB (Cluster/Standalone) Server which is used as CloudFront origin to authenticate users using JSON Web Tokens. As a result you can use the same authentication mechanism for your API and your database (at least that's what I wanted to do).
The config file needs the JWT secret to verify that the tokens are valid. If they are, the script adds Couch-Proxy-Auth headers to the backend request. Therefore it needs the CouchDB-Secret (see http://docs.couchdb.org/en/latest/config/auth.html#couch_httpd_auth/secret - at least that's strongly recommended).