Can someone help me with wiring an outlet to this junction box?

I'm in the United States.

I’ve done this before but I thought usually in a box like this I'd find the ground wires wired together and they would be green or bare copper.
And the hot wires would be wired together and be black and the neutral wired together and they would be white.

So I was expecting to see that and just add in my outlet receptacle no problem and connect the hot, neutral, and ground to the existing wire nuts but now I’m kind of confused.

In this box theres pink, white, and one black wire. PICTURE

I’m assuming white has to be the neutral wires?

So that should mean the pink ones are hot?

But what is the black wire extending out of the bottom of box? It is wired to the pink hot(?) wires and extends down the box and out of a hole in the wall. PICTURE

This wouldn’t be a ground wire would it? Why is it wired to the pink/ hot wires?

In the case that there is no ground wire in the box would I need a ground fault circuit interrupter outlet? Or do I need a self grounding outlet as well? I'm trying to read about this but am generally confused.

I'll buy reddit gold for the first person to help me understand what to do with this for whatever that is worth.