APPFS

AppFS is a universal packaging format that is presented to the system as a filesystem (via FUSE). Packages manifests as well as individual package files are lazily-fetched (Just-In-Time) and cached to disk so the "installation" step is transparent. Regular unprivileged users can read (and write!) to any file in any package, thus allowing completely unprivileged "installation" of packages and allowing users to update configuration files for the package.