It feels to me like the `appliesto` property of the CSS properties data isn't defined very specifically at the moment. For context, here is a concrete example: https://developer.mozilla.org/en-US/docs/Web/CSS/align-items#formal_definition MDN says that `align-items` applies to all elements ([data is here](https://github.com/mdn/data/blob/main/css/properties.json#L1732)). While true in the sense that it won't break if you apply it to any element, it actually won't do anything unless the element is not a grid container or a flex container. Contrast this with this other example: https://developer.mozilla.org/en-US/docs/Web/CSS/grid-auto-columns#formal_definition MDN says that `grid-auto-columns` only applies to grid containers, which is true. But also, it won't cause any problem if you apply it to any other type of containers. I would love if `appliesto` was more specific. There seems to be a lot of different values that the `appliesto` enum can take: https://github.com/mdn/data/blob/main/css/properties.schema.json#L162 and using the most specific one has advantages: it makes it easier for web authors to know why a property they're using isn't doing anything. As an example, if you're confused about flexbox and you're trying to align items using `align-content` but you did not specify `flex-wrap:wrap`, then the property won't have any effects. In this specific case, the data is actually very helpful. MDN says that `align-content` only applies to multi-line flex containers: https://developer.mozilla.org/en-US/docs/Web/CSS/align-content#formal_definition Although it's not entirely correct because it also applies to grid containers. So I have two questions in this issue: 1. Does everyone agree that the `appliesto` property should be as specific as possible for all properties? 2. Is there interest in expanding the `appliesto` enum to make it able to cover more cases? For example, there is no `gridAndFlexContainer` value now, but it would be useful in the `align-content` case. In fact, it might become useful, at some point, to allow more complex values than just strings. For instance: `gridContainer AND flexContainer` seems like it would help. As background to this, in the past I worked on this inactive-css repo with the hope to create a reusable dataset for exactly this case: https://github.com/captainbrosset/inactive-css I'd be willing to transfer this data over to mdn/data (by mapping it to the `appliesto` field) if there is interest.