Editra is described as 'multi-platform text editor with an implementation that focuses on creating an easy to use interface and features that aid in code development. Currently it supports syntax highlighting and variety of other useful features for over 60 programming languages' and is an app in the Development category. There are more than 100 alternatives to Editra for a variety of platforms, including Windows, Mac, Linux, BSD and Online / Web-based. The best alternative is Visual Studio Code, which is free. Other great apps like Editra are Notepad++ (Free, Open Source), Sublime Text (Free Personal), Vim (Free, Open Source) and Microsoft Visual Studio (Free Personal).
Jane is Just Another Nasty Editor, designed to view and edit all kind of ASCII files. There are millions of similar editors already available, but the choice is yours: those who try this might discover nice features they'll soon don't want to miss anymore.
Acme is a powerful text editor, development environment and textual-user-interface platform developed by Rob Pike originally for Plan 9 from Bell Labs research operating system, and now has ports available for all major platforms.
BabelPad is a free Unicode text editor for Windows that supports the proper rendering of most complex scripts, and allows you to assign different fonts to different scripts in order to facilitate multi-script text editing.
vy is a modal editor with a very modular architecture. vy is built on top of Tkinter which is one of the most productive graphical toolkits; It permits vy to have such a great programming interface for plugins.
4coder is a minimalist, cross platform, programmable, code editing environment, catering to the needs of low level programmers. It allows you to use one work flow across Windows, Linux, and Mac (with the exception of your debugger... for now.).