Because it is a "part" file (specifically part 6), it cannot be opened or used on its own; it requires all other segments in the sequence to be fully extracted .

The file is one segment of a multi-part compressed archive containing the full Legendary Edition of the tactical RPG Marvel's Midnight Suns .

The Legendary Edition is the most complete version of the game, including the base experience and all premium add-ons : Marvel's Midnight Suns | Official Website