The Vcs-* fields mix more than one version control system.
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 d219a5a. For merge requests, please use the latest version in the Lintian check fields/vcs.