This issue #4030 is an example of the problem. In CSS we often have one property (or selector in this case) that is not supported anywhere despite the rest of the spec being well supported.

I think there is a case for having these things documented at least minimally, because if folk have seen info about them in the spec or elsewhere (often folk write articles about unimplemented things) then they may come to us to find out how to use it.

The BCD folks don't want tables for things with no support at all, which is understandable, but it would be good to show something to developers who come and thinking the property should be supported because everything else is usable. Can we come up with a formalized statement for these cases we can put on pages, as at the moment we end up with a no BCD message, asking people to submit BCD which we don't actually want!