After upgrading from www/radicale2 (2.x) to www/Radicale (3.x), the daemon was spouting errors: "No module named 'pytz'".
In accordance with https://github.com/Kozea/Radicale/issues/816, installing devel/py-pytz resolved those errors. It should probably be a dependency of www/radicale.
Over to maintainer.
It sounds like pytz should be a dependency of vobject not radicale. At least I could not find any code in radicale that directly uses pytz.
That makes sense, thanks for checking. I've opened #249283 against deskutils/py-vobject.
If you don't mind, I'd like to keep this bug open until a decision has been made for #249283, because this problem seems to affect radicale users above all.
Fixed in deskutils/py-vobject.
*** This bug has been marked as a duplicate of bug 249283 ***