The sample implementation of a zip-archived document for macOS AppKit platform. You can implement NSDocument-based document archiving and unarchiving processes in your application like .sketch and .key file formats.
The .arcdoc document file format defined in this sample project will be archive to zip and can be unzipped on the Finder by adding .zip extension.
ZIP Foundation framework is used for the zip archiving process.
See the NSDocument implementation for details.