Google Sheets date/time render options.
Determines how dates, times, and durations should be rendered in the response.
DateTimeRenderOption()Instructs date, time, datetime, and duration fields to be output as doubles in "serial number" format, as popularized by Lotus 1-2-3. The whole number portion of the value (counting the epoch of 1900-01-01 as 1) is the number of days since 1900-01-01. The fractional portion of the value counts the time as a fraction of the day.
Instructs date, time, datetime, and duration fields to be output as strings in their given number format (which depends on the spreadsheet locale).