Question number one: what suffix should be used for those experimental packages?
experimental or incubation seem most appropriate to me. I’d prefer experimental because I’ve already updated all my code… The length doesn’t matter. Using versions in the package name is yucky, please don’t do that.
Question number two: would it be better to put the experimental API in a separate JAR file?
It would be nicer to ship it in kotlin-stdlib.jar and then when coroutines are ready for release, migrate the experimental packages, as they are, to an external kotlin-coroutines-deprecated.jar.