The tag is present in Lintian version 2.109.24. That is the most recent version we know about.
The watch file specifies a SourceForge page or download server directly. This is not recommended; SourceForge changes their download servers and website periodically, requiring watch files to be modified every time. Instead, use the qa.debian.org redirector by using the magic URL:
<project> with the name of the SourceForge
<tar-name> with the name of the tarball
distributed within that project. Adjust the filename regex as necessary.
Please refer to the uscan(1) manual page for details.