What is a blue folder in Xcode

Question

I have opened a project from Github, which has blue folders in its file structure.

As far as I understand this is a physical folder reference rather than just a means of grouping files together which might just lay around loosely on your hard drive.

So my question: When do you use those blue folders over the "normal" Group, what are its advantages and drawbacks and how do you create them in Xcode?

Answer 1

If you use blue folder references for your resources these folders will also be created inside your application bundle, while resource files in groups will simply be copied to your mainBundle's root directory.

Answer 2

When folder structure is managed outside of XCode (for example, a cross-platform project which has project files for different versions of XCode, Visual Studio and other IDEs, all using mostly the same directory tree), you normally want folder references. Otherwise one would have to recreate every project file every time folder structure changes.