On the 7.3 that would be the tube that runs up to the exhaust back pressure sensor. I have no idea if the 6.0 has a backpressure sensor but it looks like it does..
Yes basically same as 7.3 it is your exhaust backpressure sensor, what it does is measure what kind of ebp is being put out by engine and inputs that into pcm and pcm uses it to adjust the vanes in turbo for optimum performance and efficiency.
Looks like EBPV tube going to sensor, Bama. I just saw your trashed turbo so it took me a while to get here. Man, when it rains, it pours in Alabama. Sorry for your string of luck that could turn goat p**s into gasoline. Hope you get it sorted.