Howl – a general purpose editor that aims to be both lightweight and fully customizable. It’s built on top of the very fast LuaJIT runtime, uses Gtk for its interface, and can be extended in either Lua or Moonscript. It’s known to work on Linux, but should work on at least the *BSD’s as well.
Some editors offer a very bare bones default install, leaving users with the requirement to configure and add plugins to get the editing experience to a sane default. While Howl is all about things being configurable, its policy is to start off with basic features being enabled rather than disabled where it makes sense.
It is released as free software under the MIT license.