Looks very promising. I'm wondering about the current state of cross-browser compatibility.
How close are we to being able to write MV3 extensions that run on Chrome/Firefox/Safari without code adaptations?
There's standardization work being done at the moment with the W3C WebExtensions Community Group [1] which is definitely a step in the right direction!
Mozilla has also done some great work building a web extension polyfill library that attempts to abstract away the differences between the browsers [2] but the translation will always be imperfect, and edge cases are abundant.