Just the standard UAT help (pass the -help parameter on the command line). Typical usage is like this:
RunUAT.bat MegaXGE -Target1=“MyGame Win32|Win64 Debug|Development|Shipping” -Target2=“UnrealPak Win64 Development”
Which would compile MyGame in all the listed configurations for Win32 and Win64, and UnrealPak in Win64 Development configuration.