Many believe it is a defunct or "stalled" ARG. Similar to the Junko Junsui or Lake City Quiet Pills mysteries, the file serves as a MacGuffin to lead players to various websites or coordinates.
In most online "mystery" cases like this, the file is either a (a randomly generated encrypted file with no actual contents) or a malware trap designed to get curious users to download and attempt to run decryption scripts that actually infect their own systems. Cuinto7324.7z
The mystery surrounding it typically follows these narrative beats: Many believe it is a defunct or "stalled" ARG