On the south side of this library, at the far southwestern corner of the mosque, is another annex composed of a rectangular chamber which leads to a square chamber with a dome.[1][2] This domed chamber in turn once led to what appears to have been a tomb chamber located under the library, but which was later walled-up and was only reopened during renovations in 1950.[3][11] The domed chamber is richly decorated with carved stucco and with zellij tile mosaic along its lower walls, and the dome has muqarnas squinches.