The tag is present in Lintian version 2.104.328. That is the most recent version we know about.
This package appears to contain the output of running a Python "Hypothesis" testsuite.
These are not useful in the binary package or to end-users. In addition, as they contain random/non-determinstic contents, they can affect the reproducibility of the package.
You can disable generation of these files by, for example:
export HYPOTHESIS_DATABASE_FILE = $(CURDIR)/debian/hypothesis
override_dh_auto_clean: dh_auto_clean rm -rf $(CURDIR)/debian/hypothesis