SharePoint connections - Fusion Documentation

The connection caches Information about the site artifacts like Lists & Libraries. This information is used for setting up column mappings etc.

Important about Office 365 – Microsoft recommendations in order to reduce the throttling.
Use AppID/Secret as the authentication model when reading or transferring large amounts of data Also using AppID/Secret is great since you then do not have to dedicate a user account and deal with password policy and two factor authentication. Further more using the AppID you can then block Legacy Authentication for your tenant thereby enhancing security..
Here are some helpful links for creating an Office 365 AppID
How to create an Office 365 AppID (Microsoft article) Recommended “App’s permission Request XML” `<AppPermissionRequests AllowAppOnlyPolicy="true"> <AppPermissionRequest Scope="http://sharepoint/content/tenant" Right="FullControl" /> <AppPermissionRequest Scope="http://sharepoint/taxonomy" Right="Write" /> </AppPermissionRequests>` You can define your own “App’s permission Request XML” according to your need. This article is helpful to create the XML