In this blog post, Venkateswararao Alla and Udaya Polisetty describe the watchdog job feature in EMM.

A common problem with managed devices is one with inactive devices which are not in use and aren't connected to the network anymore. EMM provides a watchdog job to manage such devices.

This job continuously monitors the device connectivity and takes actions when a device is continuously inactive beyond “Device inactivity limit” (which is configured in Device Settings) based on child app usage. The possible actions are device purges and/or alert Admin.

The job depends not only on the mdm agent but also on enterprise apps. Enterprise apps connect with EMM to fetch the policy object

Prerequisite for actions based on Enterprise Apps

"Enable Enterprise Application Usage" should be configured to 'yes' in Device Settings >> Device Logs Section.

 Watchdog will consume this Enterprise App usage data to purge the devices.