The tag is present in Lintian version 2.104.234. That is the most recent version we know about.
You've specified an unknown target distribution for your upload in
debian/changelog file. It is possible that you are uploading
for a different distribution than the one Lintian is checking for. In
that case, passing --profile $VENDOR may fix this warning.
Note that the distributions
contrib are no
longer valid. You'll have to use distribution
Section: non-free/xxx or
Section: contrib/xxx instead.
Refer to Debian Policy Manual section 5.6.14 for details.