I’ve created an “Installed Build” of Unreal Engine 5.4 following the steps here:
https://dev.epicgames.com/documentation/en-us/unreal-engine/using-an-installed-build-of-unreal-engine

During this process, I noticed that the output contains two folders with similar-but-different files:

• InstalledDDC/ (114 GB)
• Engine/Windows/ (146 GB)

Both contain executables and debug symbols under Engine/Binaries/, but Engine/Windows also contains the engine source code.

Which is which? I’ve found several people asking the same question in the UE forums, but no one seems to have a conclusive answer.