Currently we delete any *.pyc file that doesn't have an adjacent *.py file, which is really overzealous on Python 3 where everything is in a __pycache__ directory. Patch forthcoming.
Created attachment 417543 [details] Patch
Committed r271443: <https://trac.webkit.org/changeset/271443> All reviewed patches have been landed. Closing bug and clearing flags on attachment 417543 [details].
<rdar://problem/73157868>