Mic,
TLDR: In MacOS 12.3, Apple introduced a requirement for cloud-storage providers supporting online-only storage to be located in ~/Library/Cloudstorage as a result of the deprecation of a kernel extension previously used by Dropbox and OnedDrive to implement 'Files on Demand'. Hence the new pathing in Pascal's email.
If you're running on an OS running dropbox that was upgraded to 12.3 plus, you'll get a warning that "some files have to be manually downloaded before they can be opened" (or some such). That's dropbox's way of providing a migration path while they work on an upgraded client. The beta version of dropbox I'm running just recently (in the last month or so) did a forced migration of my files into ~/Library/Cloudstorage/Dropbox, so I'd imagine they'll be pushing that out via a client update soonish.
from the article (written in Jan, 2022):
If you're using either Dropbox or Microsoft OneDrive to sync files on a Mac, you'll want to pay attention to the release notes for today's macOS 12.3 beta: the update is deprecating a kernel extension used by both apps to download files on demand. The extension means that files are available when you need them but don't take up space on your disk when you don't. Apple says that "both service providers have replacements for this functionality currently in beta."
From that article:
With the new Files On-Demand experience, the sync root is always located within users’ home directory, in a path such as:
~/Library/CloudStorage/OneDrive-Personal
As part of the upgrade, the sync root will be moved to this location. This location cannot be moved or changed and is controlled by macOS.
This path is a little cumbersome for users to use, so they can access this directory in two other ways:- Under Locations on the Finder’s left navigation pane.
- Via a symlink at the original location the user picked when setting up OneDrive. For example, if the user chose to sync OneDrive at ~/OneDrive, then a symlink will be created from here to ~/Library/CloudStorage/OneDrive-Personal.