The tag is present in Lintian version 2.108.13. That is the most recent version we know about.
As of policy version 22.214.171.124, Debian no longer follows the FSSTND.
Instead, the Filesystem Hierarchy Standard (FHS), version 2.3, is used. You can find it in /usr/share/doc/debian-policy/fhs/ .
Please refer to Debian Policy Manual section 9.1.1 for details.