DWV U-turn

What do you think of this U-turn in this ABS DWV system. What is the dead end stem with cap for?


Looks to me as someone changed their building plans in the middle of a job (without making the necessary code change. Is this a newly constructed home?

Or future additions

6 years old, how would you write this up?

Not sure I would if the slopes are correct.

I am questioning if the that is a long sweep el on the right side where it enters the wye fitting.

It looks like a short el and those should only be used on the vent side of the system.