From https://caniuse.com/css-anchor-positioning you'll see "All major browser engines are working on implementing this spec.".

Not all browsers implement the same features at the same time. Firefox releases some features before Chrome, so it goes both ways.

Firefox is actively working on an implementation of this to be fair (source: I work on Servo and we have been accepting a steady stream of anchor positioning changes from our upstream stylo component)

the chrome team just shovels all kinds of shit into their browser, that literally nobody uses. but it looks good in comparisons

Firefox is in good company, Safari also doesn’t.