The tag is present in Lintian version 2.104.264. That is the most recent version we know about.
The source package contains files in
debian/source/git-patches. These patches should have been exported
It does not look like the patches were exported for this source package.
You will see this tag when you generate a source package without
gitpkg (or with a misconfigured version) unless the patches
were exported manually.
See the above mentioned hook file (in
for information on how to export patches manually.