Index.mkv -

This forces Google to look for server directory listings (which usually start with the text "Index of/") that specifically contain high-quality .mkv video files.

When managing your own media library, you might encounter "index" or naming issues within the .mkv files themselves: index.mkv

The most common use of "index.mkv" is in advanced search queries (often called "Google Dorks") to find movies or TV shows hosted on open web servers. This forces Google to look for server directory

If you are trying to fix an "index" name or organize your MKV files, these are the standard tools: How to Rip a DVD Free with MakeMKV and HandBrake Easy index.mkv