This is not an answer to the question, but I noticed these headings in the recent Dhammapada: Verses and Stories from Daw Mya Tin published by Pariyatti.
I’m not sure who added them, beyond ,“an editor” (like all headings in Buddhist texts).
They represent the grouping of verses as per the commentarial stories. So visakhavatthu is “the story of visakha”. The heading is a tad incongruous, as the dhp itself does not contain the stories. The headings are imported directly from the commentary, where the actual story is found.
From the perspective of how the verses are used in teaching in Sri Lanka the headings being in the Dhammapada itself makes a lot of sense. Often the verses are experienced through the story first, with the verse coming at the end, as it does in the story. A preacher may have the story memorized quite easily and even know the vagga, but then need to double check the exact Pali for the verse.
However, I have no idea why the headings were included in this particular edition. Just that it is not so odd that someone would do it.
