The Breadcrumbs UI is quick view of an element's location in the page hierarchy. It is similar to the page structure panel (which displays the same hierarchy in a "tree" layout.)
You'll find the Breadcrumbs UI at the bottom left of the window.
How Do I Use the Breadcrumbs UI?
Any time you select an element on the stage, the breadcrumbs UI will indicate the hierarchy associated with that element, and display it from left-to-right.
In this case, the selected element is a text element, which is inside a container, which is itself inside of a grid element.
You can click on any element in the hierarchy to select it.