The isort settings import_heading_{section_name} lets you specify heading comments for the sections, each defaulting to None.

I use these headings with all of my team projects so not a second is wasted trying to figure out where a package comes from. This is especially helpful when you have only a couple imports, hence not all sections. Developers new to a team have to figure out whether a package name they don't recognize is internal or third-party. There are even standard libraries that experienced developers often don't know, e.g. ast. This time savings translates to tasks like skimming your modules to gather a precise list of third-party dependencies.