It's kind of important to use the right terminology when you are asking about part of your landrover/car and what it does/how it works. If you don't know what it's called a photo is the best and quickest way to get a meaningful reponse.
There is a lot of knowledge and helpful p[eople on here but there is also a lot of flippancy.
Using slang words/names won't attract the helpful .... just sayin.
What is the pipe the connects to the top of that pin for swivel? Is this a hydraulic pipe or squirter???? Looks like my brake pipe that goes to my caliper