I didn't do my research @gizzlon - I assumed it was backwards compatible!

Perhaps you can help - a quick Google suggests that a reasonable Perl 6 file extension is .p6 - is that standard in the Perl world?

dexec chooses a Docker image based on file extension. I'm planning to allow this to be overridden anyway, but it would be great if there is an easy way to distinguish between Perl 5 and 6 source files.