I just tried removing the build-dependency on python-autopep8 and other than file date changes, there did not seem to be any changes in the resulting packagse, so I decided to go ahead with a NMU.
While preparing the NMU I noticed that the clean target was not cleaning up properly, so I fixed that too. Debdiff is attached, NMU is in delayed/5.
diff -Nru xcffib-0.8.1/debian/changelog xcffib-0.8.1/debian/changelog --- xcffib-0.8.1/debian/changelog 2019-09-07 09:47:56.000000000 +0000 +++ xcffib-0.8.1/debian/changelog 2019-12-22 01:57:12.000000000 +0000 @@ -1,3 +1,11 @@ +xcffib (0.8.1-0.6) unstable; urgency=medium + + * Non-maintainer upload. + * Remove build-depends on python-autopep8 (downgrades: 938840) + * Fix clean target. + + -- Peter Michael Green <plugw...@debian.org> Sun, 22 Dec 2019 01:57:12 +0000 + xcffib (0.8.1-0.5) unstable; urgency=medium * Non-maintainer upload diff -Nru xcffib-0.8.1/debian/control xcffib-0.8.1/debian/control --- xcffib-0.8.1/debian/control 2019-07-26 07:27:42.000000000 +0000 +++ xcffib-0.8.1/debian/control 2019-12-22 01:57:02.000000000 +0000 @@ -22,7 +22,6 @@ , libghc-either-dev , python-setuptools , python3-setuptools - , python-autopep8 , python-all , python3-all , python-cffi diff -Nru xcffib-0.8.1/debian/rules xcffib-0.8.1/debian/rules --- xcffib-0.8.1/debian/rules 2019-09-07 09:47:56.000000000 +0000 +++ xcffib-0.8.1/debian/rules 2019-12-22 01:57:12.000000000 +0000 @@ -10,6 +10,8 @@ # we can't use setup.py clean here, since it checks for the existence of xcffib/ override_dh_auto_clean: make clean + rm -rf debian/cabalconfig + rm -rf .ghc.environment.* %: dh $@ --with python2,python3 --buildsystem=pybuild