Hillary Clinton is set to answer questions about her team’s destruction of roughly 30,000 emails when she submits testimony Thursday in a high-profile lawsuit over her State Department records.

Clinton will be forced to describe the creation and operation of the server system that was kept in the basement of her Chappaqua, N.Y. home during her time as secretary of state, as well as the steps her staff took to separate work-related emails from private ones in 2014.