It\'s not completely clear to me, what is the status of setup.cfg. I am looking for solutions for my other question about PEP 508 environment markers, and I bec
Nope, setup.cfg it is not deprecated and the documentation you mention is misleading.
There were serious reasons like security related to the fact that setup.py needed execution and that's the main reason of moving away from it.
Here is the dirty trick for extras:
[options.extras_require]
pdf = ReportLab>=1.2; RXP
rest = docutils>=0.3; pack ==1.1, ==1.3