See documentation for this project on Fuz wiki
Available endpoints:
API minimalistic documentation
{"fuzIsOpen":true,"lastSeen":"2019-11-03T16:25:24.385Z"}
The JSON means that the last notification sent by the presence button
was at 2019-11-03T16:25:24.385Z and it was saying that the Fuz was open
at the time. If it's been a while since last notification (lastSeen), we
can conclude the Fuz is now closed.