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.
The Autotoolset package complements the GNU build system by providing automatic generation of legal notices, automatic generation of GNITS-standard directory trees, a rudimentary portability framework for C++ programs, support for writing portable software that uses both Fortran and C++, additional support for writing software documentation in Texinfo and LaTeX, and a manual introducing both Autotools and the GNU build system in a unified task-oriented manner.
CMUCL is a free, high performance implementation of the Common Lisp programming language which runs on most major Unix platforms. It mainly conforms to the ANSI Common Lisp standard. CMUCL provides a sophisticated native code compiler; a powerful foreign function interface; an implementation of CLOS; the Common Lisp Object System; which includes multimethods and a metaobject protocol; a source-level debugger and code profiler; and an Emacs-like editor implemented in Common Lisp. CMUCL is maintained by a team of volunteers collaborating over the Internet, and is mostly in the public domain.
CSDE (CSharp Development Environment for X/Emacs) is a full-featured mode for CSharp development in Emacs/XEmacs. Features include font-lock, indentation rules, grammatical parsing, auto complete, automatic documentation of classes, documentation checking of classes, namespace generation, using sorting, and much more. This is a conversion of the JDE for Emacs / XEmacs to CSharp.
DictEm is an extremely customizable DICT client for (X)Emacs. It implements all functions of the client part of the DICT protocol (RFC-2229). Unlike dictionary.el, it widely uses autocompletion that is used for selecting a dictionary and search strategy. It provides several hooks that may be used for buffer postprocessing. Built-in hyperlinking and a highlighting mechanism are based on this ability. It supports the mechanism of virtual dictionaries that can be used for grouping dictionaries from different DICT servers into the client-side virtual dictionary.
Ecf (Emacs Configuration Framework) is a versatile configuration package for Emacs. It is meant for users whose Emacs configuration has become so complex that it appears to be unmanageable. It enables you to write and load the configuration for individual Emacs packages in pieces. You can use it to setup some autoloads for a package when you start Emacs and then do extra configuration after the package has loaded. This speeds up your Emacs startup without compromising your ability to do complicated things.