The tag is present in Lintian version 2.104.234. That is the most recent version we know about.
The package appears to use Python as part of its build process in
debian/rules but doesn't depend on Python.
Normally, packages that use Python as part of the build process should build-depend on one of python3, python3-all, python3-dev, or python3-all-dev, depending on whether they support multiple versions of Python and whether they're building modules or only using Python as part of the package build process. Packages that depend on a specific version of Python may build-depend on the appropriate pythonX.Y or pythonX.Y-dev package instead.
Refer to Debian Policy Manual section 4.2 for details.