Python ports should follow its upstream naming (https://pypi.org/project/python-dateutil/). Please move devel/py-dateutil to devel/py-python-dateutil and bump dependet ports.
(In reply to Po-Chuan Hsieh from comment #0) Forgot to mention the PORTNAME change.
Thanks for tracking this Sunpoet. Happy to review a diff if you'd like to take this. I wont have spare cycles for a while
Maintainer reset.
It is done in ports 84a372ad5ff0dab59a76d894d1e7fb0a5bb7b742.