css.properties.box-shadow - Mismatch between implementations and the updated spec

What type of issue is this?

Incorrect support data (ex. Chrome says "86" but support was added in "40")

What information was incorrect, unhelpful, or incomplete?

The BCD show that all major browsers fully support box-shadow since ~2011, but the spec has updated the spread algorithm several times since 2014. Chrome aligns its implementation with the spec now, and there's perceivable difference between the new and the old algorithm, see e.g. this Chrome Bug.

What browsers does this problem apply to, if applicable?

No response

What did you expect to see?

A new entry for box-shadow reflecting the support statuses for the new algorithm.

Did you test this? If so, how?

No response

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

The spec: https://w3c.github.io/csswg-drafts/css-backgrounds/
In particular, the spread algorithm: https://w3c.github.io/csswg-drafts/css-backgrounds/#shadow-shape
Chrome Bug: https://crbug.com/1322942

Do you have anything more you want to share?

There's an open issue in CSSWG about the status quo and further proposals of the spread algprithm: https://github.com/w3c/csswg-drafts/issues/7103.

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/box-shadow

MDN metadata

Start with the BCD entry for css.properties.box-shadow and review the CSS Backgrounds shadow-shape specification, especially the spread algorithm. Compare the implementation status with Chrome bug 1322942 and CSSWG issue 7103 before deciding whether separate compatibility data is warranted. Done means the entry accurately reflects browser support for the updated algorithm, with evidence linked from the change.