[csswg-drafts] [css-values-4] <position> is a lie

nox has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-values-4] <position> is a lie ==
The specification for [`<position>`](https://drafts.csswg.org/css-values-4/#typedef-position) states that the 3-values syntax from `background-position` is generically forbidden from it.

This contradicts user agents in the wild, which all accept this supposedly-forbidden syntax everywhere `<position>` is used, such as in:

* `mask-position`;
* basic shapes' positions;
* `-radial-gradient()` position.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/1338 using your GitHub account