After logging in to ArcGIS Server Manager with Administrator/Publisher role, go to Site > GIS Server > Data Stores.
Under Data Stores, you can see the registered (enterprise) databases and registered folders, whichever is applicable.
Registering your data with ArcGIS Server using Manager
You can also view it from ArcCatalog. Right-click the ArcGIS Server connection (Administrator/Publisher) > ArcGIS Server Properties > Data Store.
You can see the solders under registered folders.
Register your data with ArcGIS Server using ArcMap
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