What is the bottom half for and the black dongle?

So my radio crapped out on my 2016 Taco it kept going to ground somewhere in the receiver. I bought a similar one thinking it was the same, but in the back it seems to be missing the bottom half? As illustrated in the pic. Also I am able to connect all plugs except that black dongle as illustrated in pic. The new radio works, but I can't figure out what the black thing is for.

 

https://www.tacomaworld.com/threads/2016-stereo-wiring-diagram.429679/

https://www.tacomaworld.com/threads/oem-non-touch-xm-radio-swap-with-oem-entune-radio.525797/

 

Bottom module is XM. Black port is XM antenna

 

Pulled it all apart and found it.. thanks for letting me know broths. I'm glad I get to visit listen to my speaker again for about a year and I would play music through my phone and put in the door jam to listen to music haha