Adobe doesn't seem compelled to communicate with this community at all, so it doesn't seem likely we will get any insight to the runtime and tweening tech. It's not a production tool by any means at this point, and this is partially why. Browser support is pretty good, and performance varies greatly (as to be expected). Greensock is considerably faster, and is smaller. If you're looking to make usable production animation, don't bother with edge animate.
In a perfect world, they would trash the runtime and go full-in on canvas. Or at least provide an option to output a usable data format to then be used in a legit pipeline such as Greensock.
Thanks for the rely that is all very helpful! Such a pity, I really need a
GUI based animation tool I can make templates with for more non technical
artists and animators to tweak and work with/build upon. Potential of
animate seems so great. Maybe one day