Vox.com "Cards" Plugin recommendation?

Does anyone know what kind of widget could produce a page navigation menu like the one Vox.com uses for their “Cards”?

Example: https://www.vox.com/cards/va-scandal-explained/what-went-wrong-at-the-va

I think it’s basically a plugin that puts multiple pages on a post, but instead of “1, 2, 3” they have titles. I guess that’s ajax? I can’t even figure out what to search for to get in-post page management so if anyone can point me in the right direction that would be great.