APFS is designed to accommodate the use of solid-state drive storage across Apple's product line and address shortcomings of the long-used HFS Plus (Mac OS Extended) drive format, such as the 2040 date limit. There are 194672 days 12 hours left before the clock used by APFS itself expires on July 21, 2554 at 23:34:33 Greenwich Mean Time.
APFS-formatted drives are partitioned into "containers" in which individual volumes are assigned specific roles. Volumes with preboot, recovery, and virtual memory (VM) roles are not mounted and remain hidden by default. Starting with macOS Catalina, volumes can be organized into "volume groups" where the bootable macOS system and data are kept in separate volumes and the system is kept locked by default. The purpose of this separation is to protect the macOS system from modification by hackers.
- Working with APFS Volume Groups by Mike Bombich, Bombich Software. 2020-03-16.