These are the texture elements that you can bake.
When you add an element to render, it appears in a list on the Objects To Bake rollout. In the list, you can disable or enable rendering of that individual map, or select it to adjust which components it will include.
The available element maps are described in the sections that follow.
Many element maps let you choose to include or not include components of the rendered scene. When your element to render is highlighted in the list, these options appear on the Selected Element Unique Settings group.