The code follows the Drupal coding standards: https://www.drupal.org/coding-standards Style compliance can be checked using the Coder Sniffer extension to the PEAR PHP_CodeSniffer project, for instructions about how to install Coder Sniffer see https://www.drupal.org/node/1419988 TL;DR: install drupla/coder and enable the Drupal coding standard in PHP_CodeSniffer: $ composer global require drupal/coder $ export PATH="$HOME/.config/composer/vendor/bin:$PATH" $ phpcs --config-set installed_paths $HOME/.config/composer/vendor/drupal/coder/coder_sniffer/ And then use this command to check the style: $ phpcs --standard=Drupal .