If you have, for example, a lot of model classes and you wanted to organize them with folders, you had to add the path for each folder to the $modelPaths array in /app/config/bootstrap.php like:
$modelPaths = array('/path_to_model_folder_A/', '/path_to_model_folder_B/');
Thanks to some recent changes in the development branch this is no longer necessary. You can now create as many folders as you want within the “/app/models” folder, and CakePHP will automatically find the models in those folders. So you could have a structure like:
/app /models /A /B /C /D
A model can now be in the “models” folder as usual, or it could be in one of the other folders (A, B, C, or D). It doesn’t matter. And in your code you do not have to care about in which folder a model is stored, you use your models as usual.
What I described for models also works for controllers, components, and helpers (and probably behaviors, but I didn’t test it with them).