This all goes back to my original point: I don't want to promote people shipping around bytecode only as it hampers the use of other VMs.

Anyway, I'll continue to contemplate this. Any function would have to verify the magic number and flat-out fail otherwise to prevent parsing issues (e.g. Marc's patch works with or without the file size field to stay compatible with PyPycLoader.write_bytecode() implementations that might not set the file size field; a design flaw that I fixed in SourceLoader by taking away the ability to write bytecode). It would also have it return a dict much like path_stats() for easy comparison / verification.

But just to be very clear in case someone is hoping, I will NOT support an API to write bytecode as it make compatibility a nightmare and hampers changing the format as necessary.