How do you search for posts here that have (or don't have) a source provided? I'm sure it's mentioned somewhere on the forums, as I kind of vaguely remember seeing it in a post somewhere, but I can't seem to come up with a search query that will find it.
Also, while I'm here, is there a full listing of the meta tags one can use to search posts? I've seen fragments here and there, but nothing that has it all gathered into one convenient spot.
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