What does the Windows command 'assoc' do?

The Windows command 'assoc' is designed to display or modify the file associations of the operating system. When executed, it shows a list of file extensions and their associated programs. This is particularly useful for understanding which applications will open certain file types by default. For instance, if you want to know which program is set to open a text file with the .txt extension, running the 'assoc' command will provide that information, linking the file type with its corresponding program. This command is integral for managing file types and understanding how the system handles different file formats.