The tag is present in Lintian version 2.113.26. 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 43a81d7. For merge requests, please use the latest version in the Lintian check upstream-signature.
The packaging includes a detached upstream signature file that was armored
gpg --enarmor. That is likely an error.
Please generate the signature with
gpg --armor --detach-sig instead.