All desks now have "Desk Occupancy Sensors" installed...
Take a peek or slide your hand around where your seat is typically situated in from of your monitors. Feel a small plastic square glued to the underside?
That is a temperature activated sensor that tells 3M whether the desk is being sat in.
(Your body heat activates the device)
I can understand this from a facilities perspective. They need to know how to efficiently heat/supply/light/clean, areas of the office where there is more/less activity.
But don't think for a moment they aren't also inferring your attendance with this technology as well....
https://support.disruptive-technologies.com/hc/en-us/articles/5667520055964-Desk-Occupancy-Sensor#:~:text=The%20Wireless%20Desk%20Occupancy%20Sensor,people%20sitting%20at%20a%20desk.