Depends on what you are counting as the "same".

Edge put together a really great visualization of the API surface of all the browsers. - https://developer.microsoft.com/en-us/microsoft-edge/platfor... The API surface (and bug surface) is actually pretty different these days.

Internally Blink and WebKit are also diverging reasonably rapidly. As a specific example here is the project to re-architect how blink does it's painting: https://www.chromium.org/blink/slimming-paint

EDIT: spelling