The tag is present in Lintian version 2.104.244. That is the most recent version we know about.
debian/files causes problems for the autobuilders,
since that file will likely include the list of .deb files for another
architecture, which will cause dpkg-buildpackage run by the buildd to fail.
The clean rule for the package should remove this file.
Refer to Debian Policy Manual section 4.12 for details.