How should Intl.DTF formats in this proposal's locale relate to Temporal objects' toStriing() output?

[justingrant]

One way to specify the output formats of this proposal could be to leverage the fact that Temporal objects' toString output always uses ISO 8601 format which is what this proposal's locale will use too.

Should this proposal's Intl.DTF output formats be limited to what Temporal.*.prototype.toString() outputs?

This would provide the following formats:

• 2020-12-25 - Temporal.PlainDate
• 2020-12 - Temporal.PlainYearMonth
• 12-25 - Temporal.PlainMonthDay
• 2020-12-25T12:34:56 - Temporal.PlainDateTime
• 12:34:56 - Temporal.PlainTime
• 2020-12-25T12:34:56[America/Los_Angeles] - Temporal.ZonedDateTime
• America/Los_Angeles - Temporal.TimeZone

Note that some Temporal toString methods have options like fractionalSecondDigits for the toString of Temporal.PlainTime and Temporal.ZonedDateTime. The AOs in the Temporal proposal that implemnt these formatting options can perhaps be leveraged for DRY purposes by this proposal's spec.