After each OS update, I have seen a Relocated Items folder on the desktop (actually an alias). I never knew what to make of it but this article explains it:
What macOS Monterey's 'Relocated Items' are, and how to delete them Although I am not using Monterey, the info applies equally to Big Sur (and, I suspect, at least some OSs previous to Big Sur). The actual files took up a bit of space so I deleted them, following the procedure in that article.
This may be of interest to anyone else who wondered about it.
