What is a DUCK file? Bookmark created by Cyberduck, an open source FTP, SFTP, and WebDAV client; contains connection settings for a specific server; opens the connection to the corresponding server when double-clicked.

More Information Cyberduck bookmarks are saved in an XML format and contain the server address, directory path, port, protocol, and login information. They can created by selecting Bookmark → New Bookmark within Cyberduck. Bookmarks can also be dragged to and from the Bookmarks window. In Mac OS X, Cyberduck bookmarks are saved in the following folder: ~/​Library/​Application Support/​Cyberduck/​Bookmarks Recent connections are also saved as bookmarks in the following folder: ~/​Library/​Application Support/​Cyberduck/​History