I'm not too familiar with runtime geodatabases, but I do know that there is an Arcpy function to convert the runtime geodatabase to a file geodatabase. I know this is an extra step, but perhaps you could use this to convert before reading by FME.

More info here: http://desktop.arcgis.com/en/arcmap/10.3/tools/conversion-toolbox/copy-runtime-geodatabase-to-file-geodatabase.htm

Mad Warren is correct, there is also a geoprocessing tool coming to ArcGIS Pro 2.4 which will convert the data to File Geodatabase, so if you have ArcGIS available you can connect to the data with a startup script or scripted parameter.

Mad Warren is correct, there is also a geoprocessing tool coming to ArcGIS Pro 2.4 which will convert the data to File Geodatabase, so if you have ArcGIS available you can connect to the data with a startup script or scripted parameter.

@larryw May I ask the ETL use case for reading .geodatabase without synching it to the parent service? Thanks.

Thanks for the conversation... My issue is that the AGOL service got corrupted while data collection was out in the field leaving no place to sync the data back to using collector. Then the ArcMAP 10.5 Runtime to File Geodatabase tool would crash on the conversion. Then I went to Pro and used the Runtime Geodatase Extract to XML Workspace, and then Import XML Workspace to a File Geodatabse. So I have my field data, I now have to reconcile it with the source data using FME. Just checking if the Read Runtime Geodatabse was available...

Larry