What is the source of Xcode build settings defaults?

Question

I have two Xcode projects. Neither of them have custom ENABLE_BITCODE setting .pbxproj file. But in one of them it's set by default to YES and in another one it's set to NO. If I enable Customized filter - it's empty in both project.

Where the settings come from?

Answer 1

You can see sources of particular settings by enabling Levels toggle in build settings.