in my recollection those are either air injection or a test port. I think the only vehicle I ever owned that had that was my 80s-ish Datsun pickup (with the funky distributor that dealt with the two-plugs-per-cylinder.. I'm pretty sure that engine was on the edge for emissions certification)
2007 WK Limited 5.7L
2014 WK2 Overland 5.7L
And a few past Durangos
The pipe goes to this small thing and has a 3 or 4 small hoses and wires. I think it has something to do with a emissions. The weld broke off the cat and I've plugged the hole. I don't know if this can be deleted.