In this case, the cornerbacks and linebackers divide up areas of the field closer to the line of scrimmage, with the two safeties serving as the last line of defense.
Most coverages are identified by how the deepest part of the field will be defended. For example, a Cover 2 defense features two deep safeties, where each is responsible for their deep half of the field. Two people cover deep. In this case, the cornerbacks and linebackers divide up areas of the field closer to the line of scrimmage, with the two safeties serving as the last line of defense.