mozilla/servo — pull request #2764 by jviereck (2014-07-04 20:50:48+00:00)
Title: Add .editorconfig file at root level

As the first comment states

# EditorConfig is awesome: http://EditorConfig.org

Editors (e.g. Sublime with the EditorConfig package) use this file to setup the right editing environment (like tab size).

There is also an option to `trim_trailing_whitespace`, but I was not sure if this is useful for the project.