Agreed. My plan is to just replace the precompiled ZIP file of the standard library in the embeddable package with one with PYCs missing the "check source" bit that the old zipimport rejects. It's as simple as a 1 line change in a supporting script in PC/layout (though the actual change I made is more significant to support other use cases).

The binary and library sources are so identical this doesn't even require a rebuild. And anyone building their own distro from source using this script will hit the issue and find this bug. The only reason I missed it was because I tested against master, not realising that the new zipimport changed behaviour here. Nobody else will be blindly releasing these packages with only tests against an incompatible versions the way we do (and now I have tests).