Dragging the window around also moves the attached sheet. The use of sheets helps avoid application-modal dialogs, letting the user continue to use an application while deferring decisions about a particular window in that application indefinitely. The attached nature of sheets reminds the user which window goes with which dialog. When a document has unsaved changes, a small dot appears inside the document window's close widget. It also allows the user to determine at a glance which windows have unsaved changes.
Bundles simplify file management.
Bundles have been explained ad nauseam in past articles . Briefly, a bundle is a folder that encapsulates many related files and appears as a single item in the high-level user interface. These localized resources exist within the Clock's application bundle and may be manipulated via the UI shown above. There's a nice benefits list in this article . Again, briefly, bundles simplify installation, movement, and removal of complex systems of files and help avoid version and format conflicts among executables and libraries.