The tag is present in Lintian version 2.104.328. That is the most recent version we know about.
This package contains a program in $PATH and is named libapp-*-perl which usually implies that the upstream project on CPAN is under the App:: hierarchy for applications. Instead of libfoo-bar-perl it should be named foo-bar.
People tend to skip library-like named packages when looking for applications in the package list and hence wouldn't notice this package.
Please refer to https://perl-team.pages.debian.net/policy.html#Package_Naming_Policy for details.