Remove workspace rights (SharepointList Folder) for Admin Account

Hi all,

i have Fabric Admin Rights on our PowerBI Service.

Within the Admin portal there is the menu point called "Workspaces". 

One can see all existing workspaces, some have a friendly name - the real workspace name we know or for personal workspaces or the real user name.

Others are called "Personal workspace" followed by a cryptical UID. 

The description for these personal workspaces is "SharepointList Folder"

So, my first question is about this type of workspace. What is the purpose, what is the source and how to handle them.

Second question is: As an Admin i could assign acces to my user by using the button above the workspace list.

Now i have that workspace on my list and i can see a semantic model .

The issue is, that i can't find any option to remove the access again 😉

Opening the menu for access maintenance within the workspace shows two users with direct access. One is a cryptical name with suffix SPList. One is my user. But there is no option to remove my user from that list. The list shows my user with right "Workspace administrator". The list differs from normal workspace user list.

Thank you very much in advance