Ideally, I'd like to end up with all domains using Discourse.
Most discourse instances have a meta tag with Discourse's verion, beginning with <meta name="generator" content="Discourse.
I would get multiple results per domain, if I just searched with the tag in double quotes. How do I search for all domains, not pages for a meta tag?
I have no preference over what search engine to use or if the interface is programmatic or not.