Manual:Hooks/NormalizeMessageKey

Details

 * &$key: (string) The message going to be displayed. Change this to display a different message in its place
 * &$useDB: (bool) Whether to query the database to get the message
 * &$langCode: (string or bool) If a string, the language code that should be used to get the message, if bool true, uses the content language, if bool false, uses the site's default language
 * &$transform: (bool) Whether to expand templates and variables in the message