Is the timestamp stored in UTC or local time?¶

It depends on the source: the report may convert stored UTC for display, preserve local wall-clock time, or interpret another numeric format.

Separate storage from display¶

Establish the source field, raw value, epoch and units, recorded offset if any, and whether the parser defines device, server, UTC or local time. The viewer can display the same universal value in the examiner's, device's or selected zone, so two reviewers may see different clock times without any source change.

Make conversion reversible¶

Apply the offset and daylight-saving rule for the event date, not the review date. A local value without zone is ambiguous and should not be converted by guesswork; converting it again as if it were UTC creates error. Retain stored value, source basis, display setting and calculated result for important events.