Looking at my SQL log shipping file names (following is an example)
Q:\Backups\LogShipping\MyAudit\MyAudit_20201027165400.trn
What date time format is the transaction log expressed in (local military time, UTC time)?
What date time format is the transaction log expressed
Yes, it is UTC time with the format dbname_YYYYMMDDHHMMSS
(time is backup start time in 24 hours format). I think, following screenshot (copied from..) can help for easy validation.
Left side: Highlighted is Log Shipping backup name with UTC datetime
Right side: Date modified column indicating the time in +4 time-zone