We understand that when publishing a hosted feature layer by following this instruction, Publish hosted feature layers—Portal for ArcGIS | Documentation for ArcGIS Enterprise , the data goes into "ArcGIS Data Store."
But in the case of uploading an FDGB, is the data ended up in an RDBMS behind the scene or the data is actually stored in a folder accessible to the portal services?
If the answer is the former, as we'd suspect, does that mean the ArcGIS Data Store includes its an RDBMS engine such as Postgresql? We did not install any RDBMS as part of the enterprise installation, nor could we find any RDBMS services on the host machine. So we are baffled...