Bookmark the URL. Use it as a backup or a discovery tool for obscure global entertainment channels. But keep a free, official service like Pluto TV or Plex installed as your primary driver.
The .m3u extension stands for (or Moving Picture Experts Group Audio Layer 3 Uniform Resource Locator). It is essentially a plain text file that contains links to streaming media. When you open entertainment.m3u in a text editor, it looks like this: Bookmark the URL