This looks like it's a pre-turbo sensor... forgive me for my lack of understanding. I'm still learning.
I'm not having a go at you or anything, I like helping people who want to learn.
The orange connector like savage said is the EGR temp sensor and is no longer used. The black sensor under it is the pre turbo EGT connector. This is an important sensor.
I plugged it in on a customers vehicle after I installed a stage 2 with dpf/scr delete but wasn't latched completely so it disconnected.
It took 4 hours before I found the problem because egt sensor didn't throw a code. And I also found it out by accident as I dropped a screw and lifted the harness to retrieve it which completely unplugged it.
A failed or open pre turbo egt sensor will make the vehicle run in a severe limp mode. I think max speed was 50 kmph with foot pinned to the floor.