The package ships a watch file although it is a Debian native package. DEHS does not process watch files in native packages based on the reasoning that native packages do not have upstreams to check for new releases.
For more information please consult:
The tag is present in Lintian version
That is the most recent version we know about.
We use semantic versions.
The patch number is a commit step indicator relative to the
release tag in our Git
You can find the detection logic for this version at commit c1c05b0. For merge requests, please use the latest version in the Lintian check debian/watch.