To check what data is uploaded to the engine, please follow these steps:
Step One - Select Custom Engine Catalog from Menu>Custom Engines>Custom Engine Catalog.
Step Two - Select the Custom Engines tab and press Expand All to see your engines and select the engine you wish to check what data is on there.
Step Three - Select Versions and the the version of the engine.
Step Four - Now select the Data Catalog tab, followed by Training tab, then Training Data.