Client dashboard
Devices — where your account can be reached
One list answering one question, with two kinds of entry in it: the browsers you are signed in on, and the app installs registered to receive your notifications — which may no longer be signed in at all.
Every row carries a kind — App or Browser — the platform and version or the address it was last seen from, and when it was last active; the list is sorted by that, so anything unfamiliar surfaces at the top. The browser you are reading this in is marked This device.
The two kinds are not the same thing, and the difference matters when you are checking for something you do not recognise. A browser row is a live sign-in. An app row is a push registration: it was signed in when the app registered, and it keeps receiving notifications whether or not that sign-in is still current. An app row reading not receiving notifications has lost its registration — usually a reinstall, which mints a new one and cannot revoke the old — so it is safe to clear.
Revoking does what suits the kind, and the confirmation says which before you commit: a browser session is signed out at once and has to sign in again, while an app registration stops receiving notifications and has to sign in again to re-register. Nothing is deleted, and no messages or spaces are affected either way.
The phone shows the same list under Profile as Where you are signed in, and states each row's nature outright: an entry is either signed in and set up for notifications, or receiving notifications without a sign-in behind it — where the action reads Stop notifications rather than a sign-out.