Looks like Google "soft 404'd" the Rich Cards URL to [developers.google.com...] - tsk ;)

Bizarrely, they don't use this terminology anywhere meaningful:

[google.co.uk...]

All that said, they're referring to the examples shown here:

[developers.google.com...]

Thanks for the info!

I couldn't find anything specifically using "Rich Cards" but I wonder if it's something they're going to elaborate on at Google I/O .

In the second link I posted, Google mention that "Recipes can be displayed as an individual Rich Card ...". This seems to be they type of display they're defining as "rich cards".

They just announced Rich Cards Support [webmasters.googleblog.com]

The scope is limited, however, and there's no indication of when it will be extended:

"We’re starting to show rich cards for two content categories: recipes and movies. They will appear initially on mobile search results in English for google.com" (see rainborick's link).

In my case, I can't even test it, so including in it GSC seems a bit premature.

Welcome to WebmasterWorld NSikes

At the moment it's a little restricted to the two categories and i'm not in a position to test it.

including in it GSC seems a bit premature.

Indeed. I think Google know that a link there carries a lot of weight in terms of getting a response from site owners. Although it's going to be less and less weight if they keep plonking additional links underneath only vaguely related headings ;)

That said, this quote makes me wonder if they're ditching "structured data" for "rich cards":

We plan to migrate all errors from the Structured Data report into the Rich Card report.