BoneLab , developed by Stress Level Zero, is a physics-driven VR sandbox built on the Marrow engine. Unlike many VR titles, BoneLab offers through in-game mod.io integration. However, a separate method— sideloading —involves manually transferring custom code, avatars, or levels directly to the headset’s storage via a PC. This write-up examines what sideloading enables, how it differs from official modding, and the technical/security considerations.