Dear Maintainer, Since debian/watch points to https://pypi.debian.net/iminuit, I've packaged iminuit-2.18.0.tar.gz without issues (build is ok and all tests pass). I've also dropped longdouble.patch introduced to fix [1] (I'm not able to make a build on i386 arch).
Kind Regards [1] https://github.com/scikit-hep/iminuit/issues/753
