https://xmpp.org/extensions/xep-0310.html
XEP-0310: Presence State Annotations
This document provides a protocol using which a server is able to provide information to clients indicating that previously received presence data may be stale.
presence statexep0310annotations
https://nla.gov.au/nla.obj-2986243994/view
The Absent presence of the state in large-scale resource extraction projects
the absent presencelarge scaleresource extractionstate