The tag is present in Lintian version 2.109.3. That is the most recent version we know about.
Either the specified Python 3.x package declares a dependency on a Python 2.x package, or the specified Python 2.x package depends on a Python 3.x package.
This is likely a typo in
debian/control or due to misconfigured
calls to, for example,
Please refer to Bug#884692 for details.