floor plan of a sunken courtyard with a cap

Quick answer：

A sunken courtyard, also known as an inverted courtyard, is a courtyard that is situated below the ground level of a building. The 'cap' refers to the roof or overhanging structure that covers the courtyard, providing shelter and privacy. A floor plan of such a courtyard would show the layout and dimensions of the space, including the entryways, walls, and any architectural features such as stairs or balconies.