Nobody can explain why this user has access to a SharePoint folder

A user has access to a SharePoint folder but the source is unclear. Admins must trace inherited permissions, unique permissions, groups, guests, and sharing links before making a safe change.

This is a researched blocker from SharePoint & Teams Admins. Below is the solution path — from understanding it to a paste-ready asset.

Previews, briefings, and blueprints are open to everyone and indexed. Lessons open inside the Space once you join.