What's the best way for a site to report in-depth status to external stakeholders (customers, vendors, etc.)? Why is there no RFC on the topic?

It would be nice to have a standard (maybe specified in a dns IN TXT, defaulting to status.example.com over HTTP) returning both human-readable and machine-readable information, both current and historical.

Ideally there would be a way to accept multiple external views (from commercial uptime monitors like pingdom, or incidental to operations at a CDN, or from customer or community reported monitors), and to do reporting into specific API features or URLs as makes sense for each site or service. And being able to testify to the provenance of each monitor; say a monitoring company could attest to accuracy and freshness of reports about specific sites, helpful if you want to make a purchasing decision based on uptime over the past year.

Obviously a lot of this is specific to each site (many sites don't export an API, and many have complex APIs which are hard to monitor, and actions which are not idempotent, etc.), but just having a good framework for some of it would be nice.