> Did you manually change the status of those particular things?

No, for the specific issue you mentioned, I found and fixed a logic bug. There are some features/capabilities which are manually assigned in cases where there's no CanIUse or MDN data. (Generally, I'm trying to minimize additions/overrides for maintainability's sake.)

> For instance, I just took another look, and I saw that BackgroundSync is not marked as non-standard. But Mozilla are negative on it: […] And Apple have concerns and have not committed to it either:

This is a very fair point, and again I think you for being very generous with your time and expertise. I've reported this as a bug in the data (https://github.com/mdn/content/issues/41455), and manually overridden the data for now as a workaround.

> Personally, I would remove all the non-standard stuff. Not give a big list of standard and non-standard stuff mixed together.

I've added a "Hide Experimental" checkbox, which can also be set/shared in a URL property. I'm not yet sure about making that the default, but I hope it's useful!