Dear Maintainer, To make the build process more effecient, the "python3-flit" build engine has been spun out of the "flit" toolbox: Here is the new situation flit (the toolbox) | +-- python3-docutils | +-- python3-flit (the engine, only requires the standard library) | +-- python3-pip | +-- python3-requests: ca-certificates,: python3-certifi, python3-chardet, | python3-charset-normalizer, python3-idna, python3-urllib3 | +-- python3-tomli-w So all your package still compiles as of today. Please adapt your debian/control file accordingly: s/flit/python3-flit/ As the old "flit" package was pulling a whole more packages, your build might start to miss one of those. If you wish to keep your package backportable, please dependes on "python3-flit | flit" Greetings Alexandre