On the quick attach backhoe on my track loader one function has some extra steel lines teed into the standard lines. I think it's for the rotary swing motor. The Cat backhoe has excavator controls and it's on left joystick. More of a sloppy wobble stick than a joystick though. I'm wondering if it's some kind of relief valve or special type of valve? Just curious if someone would have a clue what the extra lines go to? You can see the lines in the pic. below.
At a glance it looks like a cross over releif system where they go in to the block at the other end is it in the return side of the valve?
You could be right about a cross over relief valve.