I’ve got 4.19 installed and I stumbled on this too.
It feels like there’s a click that was added and not “tutorialized”…
In order to look through the “Engine Content”, you need to enable the folder in the View Options (as described in the other answer). Then, you need to open the Sources Panel, by clicking on the button in the top left, under the “Add New” green button.
I highlighted the place for both these clicks in the image below:
Hope this helps.