A useful addition to the plugin might be an option to monitor cookies in use on the site, similar to how telemetry monitors remote calls. Eg. simply record every distinct cookie that is set for a user (and also track anonymous), a timestamp when first (or last? or both?) seen, and possibly cookie data (domain, expiration, possibly even the value).
This wouldn't be good to keep long term in production, but could sure be useful when people are first configuring the plugin.