One of the UUIDs used by Glass:

public static final UUID IDENTITY_UUID = UUID.fromString("f96647cf-7f25-4277-843d-f407b4192f8b");

All Glass applications (excluding GlassSystemUI) are built with a bog-standard Android SDK, hence the use of reflection to access hidden APIs and no odexing.

Glass applications use a few Library Projects, as evidenced by the multiple R.java files:

./com/google/glass/home/R.java ./com/google/glass/logging/R.java ./com/google/glass/common/R.java

Glass uses ProtoBuf like it's going out of fashion. EVERYTHING is ProtoBuf, from the communication API with Google's cloud services to the Bluetooth link with the companion app on the phone.

GpsDebugSettingsItemView literally sets up a blank screen and just logs output to LogCat.

Xenologer APKs already seem to expose the Companion connection when connected to a Linux machine:

Service Name: Companion
Service RecHandle: 0x10008
Service Class ID List:
  UUID 128: f15cc914-e4bc-45ce-9930-cb7695385850
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 3