What is this in P2V+?

[Happyflyer]

Picture below is a screen shot from the excellent video from Allem Tura on the bird side antenna upgrade(FPVLR or Horizon). My P2V does not have that board. So what is it?
Are the insides of these two quads very different?

 

[allemtura]

Thank you for the kind words about the video, I'm glad it's helping out others wishing to mod their antennas as well.

Whilst I can't help answer what it does, I can say the other end of that cable plugs into my P2V+ camera, so it must be additional electronics relating to the control or video feed.