Atom, GitHub's editor.
Introduction
Atom is a free, open-source, cross-platform text editor developed by GitHub. It is written in JavaScript and uses the Electron architecture. One major drawback is its poor performance.
Warning
On June 8, 2022, GitHub announced that it would sunset the Atom editor, and archived the Atom editor on December 15, 2022. If you still like Atom's interface, you can use Pulsar as an alternative. Its user interface is largely similar to Atom's, and its goal is to "keep their favorite editor alive"1.