Project Hailstorm references were found hidden inside the Version 2.52 update for Google Stadia on Android devices. There was no real information but the two lines “A Hailstorm is coming soon” and “Introducing Project Hailstorm from Stadia” was certainly enough to attract attention. Google hasn’t provided any real information yet about this mysterious upcoming addition to Stadia but there are plenty of theories online.
Project Hailstorm is from Stadia themselves which means this has nothing to do with the Netflix Hailstorm project from 2019. This being announced “from Stadia” suggests it’s a new Google addition which makes it unlikely to be an announcement relating to Blizzard or any other outside company. Google wouldn’t be building hype for a small announcement so it’s also very unlikely Project Hailstorm has anything to do with the recent introduction of the Shared Saved Game State feature.
In reality, there’s no way to know what the upcoming big announcement is for Google Stadia. We can be almost certain though it has nothing to do with the Shared Saved Game State update and can expect a larger announcement later.