Freeing up space · Temporary files and Storage Studio's own footprint
What temporary files does Storage Studio measure and offer to clear?
Short answer: It measures your Mac's two disposable areas — the temporary area cleared at restart and the cache area macOS empties when tight — names the app behind what's there, and offers to clear folders that pass its safety checks.
Your Mac sets aside two areas that are, by its own definition, disposable: a temporary area it clears when you restart, and a cache area it empties by itself when the disk gets tight. Apps write to both knowing the contents can go at any moment.
Storage Studio measures both and attributes what's there to the app that put it there, so a large leftover stops being "space nobody can account for". It only offers to clear a folder after checking it on its own — see how it decides a folder is safe. Anything it clears goes to the Recycle Vault, so it's recoverable.