Open 0xr.space, press Open and choose the compressed .glb or .gltf. Draco geometry (KHR_draco_mesh_compression), meshopt geometry (EXT_meshopt_compression), KTX2 Basis textures (KHR_texture_basisu) and quantised attributes (KHR_mesh_quantization) are decoded in the browser, on a computer, an Android phone or the Meta Quest browser and app. Files from gltf-transform, gltfpack, Blender's compressed export and Sketchfab open this way.
The decoders are fetched only when a file uses them. Compression makes the file smaller, not the model lighter: once decoded it has as many triangles and texture pixels as before, and a Quest still has to draw them. Where the GPU reads ASTC, as on Quest, KTX2 textures stay compressed in memory.
Yes, in the Quest browser and in the Model Explorer app, as do meshopt and KTX2.
Not by itself. Draco and meshopt shrink the download; to draw faster, reduce the triangle count and texture sizes too.
It still opens. An extension this app does not read is skipped and the model is drawn without it.
No. It is read on the device, and nothing is sent to a server unless you create a share link yourself.