If you really use Docker Desktop (and not just docker-ce on Linux Desktop) then the volume are inside the private utility vm that runs the docker engine.
If you feel you need to access the files from the host, then you probably want to do something that is not supposed to be done. I use docker since roughly 9 years, and it was never necessary to access anything from /var/lib/docker.
I am surprised that the forum search seem to not yield any good results for you, which is odd, as this sort of questions has been asked and answered a lot.
@meyay is so right, this was the exact reason why I wrote about this in my tutorial
I learned a lot while I was witing this tutorial. Why? Because as meyay, I never cared about where how I could directly access these folders. I honestly believe when people ask these questions, they ask the wrong questions, because they don’t know what volumes are for.
In the Docker Desktop setup, volumes are stored in a hidden directory. It’s like finding hidden cars in the (moderated link) game! The volumes are usually managed by Docker, and accessing them directly might not be straightforward. Consider it Docker’s way of parking volumes in a virtual garage.