An M3U (Moving Picture Experts Group Audio Layer 3 Uniform Resource Locator) file is a plain text file that stores a multimedia playlist. It contains a list of locations of media files, which can be audio or video, and can be local files or streaming URLs. The 'UTF-8' part indicates that the file is encoded using the UTF-8 character encoding, which allows it to support a wide range of characters from different languages. M3U playlists are commonly used to create and manage collections of music or video files. Media players use the information in the M3U file to locate and play the specified media files in the order they appear in the playlist. The playlist can be edited to add, remove, or reorder the media files. M3U files are relatively simple and widely supported by various media players and operating systems, making them a versatile way to organize and share media content. They are often used for internet radio stations and podcasts, as well as for creating personal music libraries.