Accesso to resource code loaded by EditorGUIUtility.LoadRequired

Been exploring few new features that will impact my assets.
So exploring unity source code I got that there are few bundled resource like shaders load using EditorGUIUtility.LoadRequired
How can i access to the code ? Those are not present on git and also not present in additional package.
Example is a shader loaded using EditorGUIUtility.LoadRequired("Brushes/CreateBrush.shader")

 

To answer your reported post question:

This is a general question and not beta related, thus staff or other mod has moved it.
Beta forums are not for general help, only for feedback on new features.

Note: it's expected posts will be moved, deleted or locked without explanation in beta areas or areas where we need a much better signal/noise ratio.

 

Ok . understood . thanks a lot