An early Horizon Forbidden West alpha build has leaked in its entirety online. As you might imagine, the build is from early on in the game's development, and it also includes a debug menu that could give some insight into the inner workings of the game's Decima engine.
This news was originally revealed by prominent leaker Lance McDonald, who tweets as @manfightdragon. In a now-deleted tweet, McDonald includes a link to a repository that hosts the full Horizon Forbidden West alpha build. After the tweet was deleted, the build was picked up by Redditor mentalexperi. We've speculated about the future of Horizon Forbidden West before, but this build represents a glimpse into its past.
According to a comment underneath the build's code, the Horizon Forbidden West build was originally intended for alpha testers to work on remotely, which might explain the leak. Testers working from home naturally have less direct oversight, so it would be easier to let a build like this slip, either accidentally or purposefully.

Being an alpha build, this leak is likely to be full of bugs, glitches, and unfinished elements. In addition, you'd need a jailbroken PS4 to run the build, and since even an alpha build of Horizon Forbidden West is Sony property, downloading the build in the first place probably isn't a good idea either.
At any rate, the existence of this leak isn't great news for Sony. While it's true that most gamers won't be able to run it or won't want to, this is still a leak pertaining to a major Sony title, so it may well not remain online for much longer. Don't be surprised if the Sony legal team swoops down and forces it to be removed in the near future.
Since the COVID-19 pandemic led to an increase in developers working from home, we've seen an increasing number of "major" leaks like this one recently. Perhaps the most egregious example is Rockstar's Grand Theft Auto 6, early footage of which was leaked by a hacker recently. Said footage even managed to land Coffee Stain in hot water (no pun intended) when the studio used it as part of a Goat Simulator 3 ad. Naughty naughty.
It's not just newer games, though; older titles are also being leaked, giving often-fascinating insights into their development. Just a couple of days ago, Mortal Kombat 2 source code was leaked, showing unused sprites and animations, and an early sidescrolling version of the ill-fated Duke Nukem Forever also appeared online recently. Make sure to stay tuned to TechRaptor for more news about leaks and all other things gaming.