Does Glass required proprietary binary blobs to be combined with the GPL source like the Nexus devices (pinning you to a narrow range of kernel versions), or is it actually open through and through?
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.
I guess I will point out that this doesn't seem to be the case. As we see from this very post the kernel sources are released, and from the earlier posts we know Glass can be unlocked with the standard Nexus style 'fastboot oem unlock', so Glass (at least through Google, who knows what other OEMs might do) will be as open as Nexus phones from what we can tell.