When does Windows hide file extensions by default in File Explorer?

Windows hides file extensions by default in File Explorer for known file types to provide a cleaner and more user-friendly interface. This setting is meant to simplify the user experience by preventing confusion caused by unfamiliar file extensions. Users can change this setting by going to the "View" tab in File Explorer, selecting "Options," and unchecking "Hide extensions for known file types." This allows users to see the full filenames, including their extensions.