Settings → Sign-in history lists your own recent sign-ins to this account, newest first. Each row shows when you signed in, the first part of the network address and the device. Only you see it.
What a row means
Each row is one sign-in. Look through the list for a time or a device you do not recognise. If one appears that is not you, change your password.
What we keep
We keep only the first part of the network address, never the full address, and we remove entries after 90 days.
What the list does not show
Only sign-ins made through this app's own login page are listed. An empty list therefore does not prove that nobody signed in. Sign-outs are not recorded yet.
If the list cannot be loaded
If the history cannot be loaded, the screen says so. It never shows an empty list in place of a list it could not read. If the feature is switched off for your workspace, the screen says that instead, and the Settings entry is not shown.