Allows customization of: * the sender address of the email * the recipient addresses * the text used to prefix the subject line * the HTTP status codes to send emails for * the error classes to send emails for * alternatively, the error classes to not send emails for * whether to send error emails or just render without sending anything * the HTTP status and status code that gets rendered with specific errors * the view path to the error page templates * custom errors, with custom error templates * define error layouts at application or controller level, or use the controller's own default layout, or no layout at all * get error notification for errors that occur in the console, using notifiable method * Override the gem's handling and rendering with explicit rescue statements inline.