I would almost expect the 3 in urllib3 to be the major version and if something needed to break it would become urllib4. Which, I know, is terribly naive of me. But that is how psycopg does it.
That was how psycopg2 did it, but now the package is psycopg (again) version 3, as it should be. Python package management has come a long way since psycopg 1 was created.
urllib2/3’s etymology is different: urllib2’s name comes from urllib in the standard library.
