Aquamacs is a Mac-like version of the powerful Emacs text editor that runs as a standard OS X application. It features extensive customization that enables it to conform better with Apple's standard Human Interface Guidelines (HIG) than standard versions of the editor do. It provides a more Mac-like user experience than Carbon Emacs.
Xtla is the Emacs front-end to the GNU Arch revision control system. It provides user-friendly wrappers for tla native commands and some higher level features such as the bookmark manager. The main features are a PCL-CVS-like interface for tla inventory and tla changes, an archive browser, good integration in Emacs, a bookmark manager, integration with ediff, Emacs's graphical diff tool, an interface to view missing patches from all your partners with a single command, and an Emacs mode for arch-related files (log files, =tagging- method).