Unfortunately, as mentioned in another comment, the Bluetooth stack is apparentl...

Unfortunately, as mentioned in another comment, the Bluetooth stack is apparently one of the items that is not included in the source release[0]:

    Some parts of the firmware have been removed for licensing reasons,

including:

    [...]

     - The Bluetooth stack, except for a stub that will function in an emulator

    [...]

Which suggests that the Bluetooth stack wasn't entirely of their own making, so perhaps any of Pebble's own additions were too intertwined (e.g. gave away too much Bluetooth stack vendor proprietary API info) to be easily separated?

[0] https://github.com/google/pebble/blob/3b927684809fba173ee540...