DSKIN is an extension given to files that are used by the OS X GUI element, which is a kind of taskbar. It is called the Dock. DSKIN files are used to store skins that allow you to change the appearance of the Dock bar. They are created using the DockX application. Technically speaking, DSKIN is a collection of PNG image files and one PLIST file.

DockX has a collection of ready-made DSKIN skins, but the user can use this tool to create their own projects according to their needs.