X-37B will change its orbit (or perhaps it already has) in order to dispose of service module components, dropping them off to burn up in the Earth’s atmosphere.
Besides this novel maneuver, the public knows very little about X-37B. It is an unmanned, remotely controlled spaceplane Boeing developed for the U.S. Department of Defense. More broadly, spaceplanes are hybrids between airplanes and spacecraft that can orbit the planet like satellites but also land back on Earth like passenger planes, per Gizmodo’s Passant Rabie. In essence, this ability makes them reusable.