Howl is 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.
This is a companion discussion topic for the original entry at https://copr.fedorainfracloud.org/coprs/atim/howl/