I got them. I believe that is a port for the PCV system. See the attached picture to see if you see any of the hoses I highlighted.
As far as the traction control and ABS, that is most likely related to a wheel speed sensor issue. Also, if a sensor fails, you get both lights. And they are different than the booster. Have you ever pumped the brakes on the truck with the engine off? If not, try it. You will find that the pedal will get really hard to push. That is because there is no engine vacuum supplying the brake booster. The booster is nothing more than a component designed to make it easy for you to press the brake pedal and easier to actuate the brakes.
By the way, the vacuum leak you found is certainly the cause of the two lean mixture codes you indicated. The engine is drawing unmetered air through that opening and causing the codes to set.
Let me know if the picture helps.
Monday, December 23rd, 2019 AT 10:41 PM