Apps · The Apps window and launcher
Which folders does Storage Studio look in for apps?
Short answer: It scans the main Applications folder, your personal Applications folder, the Setapp folder and Utilities, plus apps already on your fast drive. Protected system apps aren't offered for moving.
Storage Studio scans the standard places apps live on a Mac: the main Applications folder (shared by every user), your personal Applications folder in your home folder, the Setapp folder, and Utilities. It also shows apps you've already moved to your fast drive.
Apple's built-in system apps live in a protected, read-only part of macOS and can't be moved, so they aren't offered. When you bring an app back, it returns to exactly the folder it came from.