Now that there is mesh.uv, mesh.uv2, mesh.uv3 and mesh.uv4
Does anyone know how I can obtain which uv coordinates are used by lightmapping through the API?
Or is this always uv2?
UVs for baked lightmaps are always uv2. If you use realtime GI then the per instance UVs automatically generated for lightmap static objects occupy uv3. That’s fairly hardcoded and is unlikely to change.