Given a piece of bakery, how can you tell if it was made with yeast or
baking powder?

I want to be able to do this in order to make things that I don't have
receipe for.

Let me make a first attempt: if there are large, uneven bubbles inside, then
it is made with yeast. If the texture is even and spongy, it is made with
baking powder/soda. Right?

Using this guide, that I would guess that corn bread is made with baking
powder. But why? Afterall, shouldn't bread be made with yeast, by
definition??