What does Class extension on a file means?

A class extension on a file refers to the additional characters or suffix added to the filename to indicate its format or type. For example, a file named "document.txt" has the ".txt" class extension, denoting that it's a text file. Class extensions help operating systems and applications identify how to handle or open the file, ensuring compatibility with the appropriate software. Different file types may have specific extensions, such as ".jpg" for images or ".pdf" for documents.