That’s the file structure of a Blu-ray disc that’s been unencrypted. Get MakeMKV and open the main directory using that software. It will read it as if you’ve given it an actual Blu-ray disc. It will show you the available video files. The largest one will be the movie, so if you want, you can select only that from the list and it will rip it out of the file structure and give you an mkv file of the movie. It’ll be large because it’s not compressed, so to save space, you can use Handbrake or ffmpeg if you’re nice with command lines to encode it to your favorite codec.

This is a Blu Ray dump. Loading up Index.bdmv in VLC or your media player of choice should run the disc as if it were a real disc.

that’s the structure of a bluray disk. It includes all that the player needs to play it (e.g. menus, chapters, etc). The STREAM folder contains the actual video, probably in a .m2ts file (you can convert it to mkv using ffmpeg or similar tools)

@Joseph_Boom I just go to the biggest file, and it is usually the movie