You may find a “Purgeable” storage space when looking at disk storage and disk usage in modern versions of macOS, including Big Sur, Catalina, Mojave, Sierra, etc, either within the About This Mac > Storage screen, Disk Utility, or the Storage Management section of System Information.

This curiously labeled disk storage item is similar to the “Other” storage space on the Mac that many users wonder about, so if you’re curious what purgeable storage space is, and how to free it up to clear it out, then read on.

Source: Purgeable Storage Space on Mac: What it is & How to Free It