MAC BES Agents: How to determine if a restart is needed

How is the Bigfix determining if a restart is needed for MAC agents? Is it trying to check for any specific config files?

The method is the same as on UNIX agents. The boot time is recorded when a restart is marked as required and if the time isn’t the same as the current boot then the OS has been restarted.

Is there any specific file or maybe a relevance statement that can get us the info of when the boot time is recorded when a restart is marked as required and of the current boot time?