It’s funny that they have their own corner of the web where they own the entire API and the rest have to follow. Just because Mozilla and Apple share most of the API it doesn’t mean that Google won’t change it, in fact Manifest v3 is coming soon.

Mozilla has implemented additional APIs that are never going back into Chrome because Google doesn’t care and doesn’t have to.

Although Google is actually moving toward the standard in Manifest v3: https://developer.chrome.com/docs/extensions/mv3/intro/mv3-o... (mostly with a Promise-based API)