[shabble]

Does this mean all the current "Markdown" implementations out there are in violation of this licence term[1]?

How would one reasonably convey that their formatter is markdown-capable?

It would seem to me that there's a significant difference between "Bloopdown - a Markdown compliant formatter for blah" and "Markdown v3.Ice-cream-pony"; the latter clearly trading off the name of the original, while the former is descriptive.

I'm not sure where "$X Flavored Markdown" falls on that scale, although I'd be surprised if something like GitHub hadn't sought permission or clarified the naming provisions.

[1] Having checked a couple of different projects, none of them mention having sought or received that permission, but I suppose they might have