After logging in, macOS may check for system software updates, run an initial Time Machine backup, and run XProtect Remediator scans. This is how those happen.
CTS
Apps often have to use separate services to perform privileged tasks for them, or run time-consuming activities in the background. XPC is how the client communicates with those services.
In a quest to reduce the number of processes running in macOS Tahoe, consider the example of Time Machine backups, which can easily be replaced by 3rd party alternatives.
Users should be given a third option to defer updating further, as well as doing it now or later tonight. Does the DAS scheduling and dispatch system rely on security through obscurity too?
How DAS gathers its budgets and loads lists of activities. When rescoring permits, it then dispatches the process to initiate backup. Re-scheduling has changed in Sequoia, as shown here.
Easy to code, these don’t need to use XPC although it’s used by the DAS-CTS scheduling and dispatch system. They aren’t run at constant time intervals, but when appropriate according to other loads.
How does XProtect Remediator scan your Mac once a day? What has gone wrong when it doesn’t appear to work? Explained from its property lists to its three different types of scan.
There’s normally more than 500 background activities, like Time Machine backups and XProtect Remediator scans, waiting for dispatch in the list maintained by DAS. How this works.
Since 2005, macOS has had the master launcher launchd and its LaunchAgents and LaunchDaemons. Then in 2014 Apple added Duet Activity Scheduler to run tasks when conditions are suitable.
Automatic Time Machine backups aren’t scheduled to run at precise times, but when it’s convenient. This explains how, and what to do if goes wrong.
The Eclectic Light Company 