Unity's lowest level tool is the Frame Debugger. This tool breaks down a segment of time into frames. Then, you can look at each draw call at a specific frame:

With the game view open, you can select objects in the list and see them appear. If you ever had any questions about a render pipeline and how it composites, this can answer a lot of questions.

With that, we go to the last tool in the list, and an even lower-level tool.