Anybody recognize this?

This is not in my 20 Tundra. Found it under driver side rear threshold. 1st thought is it's a tracker which it may be but it's in series with the red wire so it's part of the circuit.

 

maybe side mirror lights or trunk remote lock?

 

What are the 2 colors on the wire it t's into? it looks like it splits that red, across its red and yellow wires, so we can only guess based upon what the control signal is coming from, which would be that T connection, at least it appears from initial photos.

 

My guess:
Those door sill sticker/decals or whatever they are look like they might be illuminated.
May be a tapped-in power source to power them when the door is open.
Is there one on the passenger side?
As stated, just a random guess..
I could be wrong, it wouldn't be the first time..

 

It's for the ejector seat and parachute.