GLTF and GLB
A GLB file (. glb), which stands for “GL Transmission Format Binary file”, is a standardized file format used to share 3D data. Precisely, it can contain information about 3D scenes, models, lighting, materials, node hierarchy and animations.
On a desktop browser the GLB will rotate in 3D space and allow the user to pan and orbit the model. On a mobile device an AR prompt will appear and allow one to view the model in situ by converting the GLB to a USDZ at runtime. Embedded animation will likely not play.
USDZ
USDZ is a 3D file format created by Pixar. It has been adopted by Apple as their format for AR applications on iOS AR Quick Look.
On a desktop browser the USDZ is a download link. However, on a mobile iOS device an AR prompt will appear and allow one to view the model in situ.