Post Processing Volume confusion (Unity 2019 LTS)

Hi, I guess I am just too stupid. I ran through the documentation several times, watched several videos, but somehow it just does not work or click with me.
When I first create a new project with the URP, the scene with the workbench and drywall is loaded. It is colour graded and stuff, has post processing on it. Yet, neither the camera nor the Post Process Volume object have a special dedicated layer added, they are both "default" (documentation suggests otherwise). Also, no Post Processing Package is loaded with the scene, I found none in the assets. Also the main camera has no Post processing volume layer, and the only thing that actually has a script component is the Post Processing volume, which has a "volume" script.
When I do a search in the scene, no Post Processing Volume scripts like volume or layer are found. The Post Processing profile has a different icon than when You create a new profile (coloured wheel in that case).
I really dont get any of this. I mean I can stumble through it, and copy the stuff and add it into a new scene, but that is not what the documentation states, which advises to add this to the camera, that to either the camera or a Post Processing Volume object etc. What gives ? Really frustrated here. That demo scene is so contradictory to the documentation, and wasnt that example scene made to actually help beginners ?