Firewall Firmware Schedule Date - Local Time vs UTC

I just scheduled a firewall upgrade for "2023-04-01T17:00:00.000Z", and the Central UI reported that it would done at on April 1 @ 17:00 local time, and it did indeed do the upgrade at 5pm local time.

I would have expected that a time in the format "2023-04-01T17:00:00.000Z" is UTC.

Could the documentation please be updated to indicate that even though the time format is specified in Zulu/UTC format, it is actually local time.

James