A Stremio add-on is a plugin that extends the functionality of the Stremio by adding new content sources, features, or streaming options. These add-ons can provide access to movies, TV shows, live channels, subtitles, and metadata by connecting Stremio to different online providers. Some add-ons are official and available directly through Stremio’s built-in catalog, while others are community-developed and installed via external links.