Which features of the TC39 committee's ECMAscript (ES) language governance model would be helpful to incorporate into the Python language governance model?

Having “beta” or “alpha” editions of features, special versions of the interpreter people can test out to see if they prefer the version with the new feature. To prevent splintering, the main releases would only support the main feature set. In a worst case scenario, people can compile incompatible code to .pyc before running it.