Mode line

Files should have Emacs and vim mode line comments as the first two lines of the file, which should set indent-tabs-mode to nil. For new files, use the following, specifying two-space indentation:

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

Be sure to use the correct Mode in the first line, don’t use C++ in JavaScript files.