I think I've found the issue: the upstream tarball contains a symlink to an non-existing target:
siretart@debian-devel:~/undertaker$ ls -l undertaker-1.6.1/undertaker/validation/cnfmodels lrwxrwxrwx 1 siretart siretart 27 Nov 26 2014 undertaker-1.6.1/undertaker/validation/cnfmodels -> ../kconfig-dumps/cnfmodels/ While I agree that this is not an ideal situation, I'd argue that dgit should handle this situation gracefully, which in this case means importing a dangling symlink. Or, if that's difficult, at least not fail while importing. Thanks for considering. Reinhard