[Sedate] Can offsets like [+02:00] be used instead of IANA names in brackets?

[Justin Grant <[e-mail]>]

The current ABNF for the time zone extension does not support offset time
zones, e.g. [+08:45]. Offset zones are supported in java.time, which is the
prior art driving the bracketed time zone extension format. Should the
standard also allow offsets in brackets too?

https://github.com/ietf-wg-sedate/draft-ietf-sedate-datetime-extended/issues/12
has discussion relevant to this question.

FWIW, in the design of Temporal we've assumed that we should support
offsets in brackets for compatibility with Java. Here's a Java example:

public class MyClass {
    public static void main(String args[]) {
      java.time.ZonedDateTime zdt =
java.time.ZonedDateTime.parse("2021-12-09T00:00-08:00[-08:00]");
      System.out.println(zdt.toString());
    }
}

Cheers,
Justin Grant