PlainTime.from() parsing but discarding offsets and time zones is surprising

[eemeli]

With the current spec, this happens:

Temporal.PlainTime.from('12:34').toString()    // '12:34:00'
Temporal.PlainTime.from('12:34+19').toString() // '12:34:00'
Temporal.PlainTime.from('12:34+99').toString() // RangeError

As far as I can tell, only the PlainTime endpoints support parsing a string without a date component, and the syntax for that includes AnnotatedTime, which includes offsets and annotations that must be correct if they're included. However, those offsets and annotations are ignored in the returned PlainTime.

This is kinda weird. Would it not make sense to require the string value not to include any offset or annotations? I've looked through the history of proposal, but I was not able to find any rationalisation for the support of time+timezone strings for PlainTime.