I don't know specifically about the drivers in Glass but it's based on the pretty old TI OMAP4 platform which was in the Galaxy Nexus, and I think out of the SoC manufacturers TI is (well, was, since they stopped making OMAP) the most open by far.
edit/clarification: These won't be blobs in the kernel but they'll be IMGTec binary libraries. So in practice it's slightly less annoying for kernel hacking.