The source package refers to a Standards-Version which never existed. Please update your package to latest Policy and set this control field appropriately.
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 25e9483. For merge requests, please use the latest version in the Lintian check fields/standards-version.