I've forked the source package for ipykernel to retain (for now) the python2 version.
(Rationale: while there aren't rdeps, keeping this package is needed to keep the ability to use python2 jupyter notebook. This package is flagged py2keep; I don't think dropping python2 here frees up many other rdeps until and unless ipython2 can be dropped). The forked source package (ipykernel-py2) has been sitting in NEW since 2019-11-17. In principle dropping python2 from this source package doesn't have to wait for it to be accepted, but I preferred to maintain continuity.
