There is a file in the package whose name matches the format emacs or vim uses for backup and autosave files. It may have been installed by accident.
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 fac7222. For merge requests, please use the latest version in the Lintian check files/unwanted.