To all whom it concerns: Following Dmitry's notes about source package name being incorrect, I have uploaded a renamed source-package to Mentors.
You can download the package with dget and this command (with -ux because you don't have my keys): dget -ux https://mentors.debian.net/debian/pool/main/p/python-imaplibext/python-imaplibext_0.7.6-1.dsc The ITP bug title I had attempted to set was too long it seems for a command to control@ but the source package name in the ITP title has been updated. The RFS has been retitled accordingly as well. (this was suggested in #debian-mentors via IRC)