Here is a design proposal for the permissions management part.
The idea is to have a table with one row per extension. When clicking a row, the row unfolds to display a nested table which contains one row per role and in each row, a select2 containing all the permissions assigned to the role and allowing them to be managed.

Here is a design proposal for the permissions management part.
The idea is to have a table with one row per extension. When clicking a row, the row unfolds to display a nested table which contains one row per role and in each row, a select2 containing all the permissions assigned to the role and allowing them to be managed.