What is "atom"
Atom is a text editor that was actually built on top of the Chrommium browser (the open source version of Chrome). All this to help in the visualization of the code on the time for the programmer.
It has an API for the implementation of packages and also themes, which makes it very customizable. Most packages are made in Coffescript and Less, but had some things in javascript and css that would be equivalent to the above.
Because it is highly customizable it has had the adhesion of a large number of developers in a short time. Because it has a wide range of features in package format, and even when they do not exist, a very complete API support is offered for its implementation.