UE4 - Intermediate Blueprint Programming - Hidden content files
A cool trick to access ue's hidden content files, by default its hidden but a simple lookup of a default mesh would reveal them all.
Also you can restart UE if you dont want to see it anymore.
Also also there's 2 more alternative methods to change it, one is to go in your game engine's .ini files and enable it manually there using a code, the 2nd method is to go to project settings, i never used either of those methods but i know its possible