-Do not delete debian/files. When do you want to use this? Anytime you have a
-debian/rules that has 2 binary targets that build different .deb packages;
-for example, one target is binary-arch, and the other is binary-indep, or
-one target builds the shared library, and the other the -dev package. If you
-didn't use -k in these cases, then debian/files would be deleted in the
-middle, and your changes file will only contain the last binary package that
-was built.
+Do not delete debian/files, or files listed in debian/clean. When do you
+want to use this? Anytime you have a debian/rules that has 2 binary targets
+that build different .deb packages; for example, one target is binary-arch,
+and the other is binary-indep, or one target builds the shared library, and
+the other the -dev package. If you didn't use -k in these cases, then
+debian/files would be deleted in the middle, and your changes file will
+only contain the last binary package that was built.