To be quite clear: this change requires discussion on the Web-SIG and an
appropriate revision of the PEP.  Ideally, the patch should include the
necessary PEP revision.

The Web-SIG discussion regarding a switch to bytes should also take into
consideration the effects of running 2to3 on existing WSGI applications
and/or servers.  Will their code be converted to use bytes, or Unicode?

The previous choice to use Unicode was based on source compatibility
across Python implementations, so this shouldn't be thrown out on the
basis of simple expediency.