The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of the browser. It is designed for Firefox, Flock and Seamonkey, and will run on any platform that these browsers support including Windows, Mac OS X and Linux.
Adds keyboard shortcuts to change folder, move/copy messages, with folder name auto-completion (using only the keyboard). Same for tags. Also includes a system of rules to suggest a target folder for saving messages; re-creates Eudora's Alt-Click; facilitates navigation in the 3-pane window; makes it easy to change between To/Bcc/Cc fields in the composer; facilitates tag-oriented operations. All that with the keyboard only!