The upstream source contains an .svn directory. It was most likely included by accident since Subversion version control directories usually don't belong in releases. When packaging a Subversion snapshot, export from Subversion rather than checkout. If an upstream release tarball contains .svn directories, this should be reported as a bug to upstream since it can double the size of the tarball to no purpose.
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 131c0f4. For merge requests, please use the latest version in the Lintian check cruft.