To read the Google Drive activity of the files or folders you monitor.
Each Google add-on also gets the userinfo.email and userinfo.profile scope. Your email address is captured to determine if you are a (free) @gmail.com user or a Google Workspace user. This information is used to determine the available Google features (e.g. script run time). Your email address might also be used to inform you about the product features / updates.
No other information is used. Your data remains your data. Your data is not read by humans and not used for any other purpose then to serve you the add-on functionality with the best experience possible.