https://wccftech.com/microsoft-testing-windows-10-reserved-storage/

As reported earlier this week, Microsoft has been planning to introduce a new feature called “reserved storage” to set aside some disk space (7GB!) exclusively for Windows updates, system cache, etc. Microsoft has today released Windows 10 Insider Preview Build 18312 (19H1) to Windows Insiders in the Fast ring, beginning the testing process.

“Through reserved storage, some disk space will be set aside to be used by updates, apps, temporary files, and system caches,” the company wrote. “Our goal is to improve the day-to-day function of your PC by ensuring critical OS functions always have access to disk space.”