Cummins Compressor Air Return Line

2018 LT
Cummins X15

There is a small silver airline that appears to return air pressure to the compressor intermittently that is broken off on my engine.
Don't know how it happened.
Just happened and I'm in the middle of nowhere.
Is this safe to drive to a shop?
What does that airline return air to the compressor for??
Any help would be great.

 

This was resolved with a new connector.
I haven't found out what the line does.
It is under pressure while under power.
No pressure when slowing.
Intermittent pressure while parked.
It's fixed of course, but if anyone knows what the line does, please post for reference.
Thanks