GSDocument

nil when the document has no window controller, as is the case in a framework-only host.

Reads a document of a type handled by a file format plug-in into the receiver.

Reads a Glyphs document, a Glyphs package, or an icon set into the receiver.

The file format plug-in class that reads typeName, or nil when no plug-in handles that type.

Prepares the font for being written to disk.

Whether changes to a file of the given type are tracked while the document is open.

Starts observing the document file for external changes.

Stops observing the document file for external changes.

Re-establishes the observers for the files inside a document package.