What is a breadcrumb?

Sorry if this question is too basic. What is a breadcrumb in the context of notetaking? I see the word used in discussions here, and I’m not sure how to spot one in my remnotes.

Using the tutorial documentation as an example, breadcrumbs are just the “steps on a path” taken from the top level to get to the rem you are viewing. A top level rem would have no breadcrumbs.