Note to QA:
Using folder as an example Content Type might also require adding the following permission to be able to see "Content -> Content structure":

Content / Read:  Location: /Ibexa Digital Experience Platform

Steps to reproduce:

1. Create a new Role with the following policies:
   
2. Create a new user and assign it to the Role.
3. Create a new folder somewhere with a child folder inside as newly created user. Save both folders' URLs.
4. Change content/read role and add Content Type Group:self policy to it.
5. Access both folders again, and check the Subitems table.

Result:
One can access both contents' views in the Content Tree, however, the parent folder subitems count is 0 and there is no child folder to be found there, even though the folder is accessible through the URL.

Expected result:
The subitems list in the parent folder should show the child folder.