In the Date/time properties (Sec 3.8 of wd2), there are two issues:

1. second field is constrained to 00-59. this should be 00-60 to account for the possibility of leap seconds as allowed by ISO-8601 and POSIX.
2. it seems like an arbitrary constraint to only allow second and millisecond precision. I think this should be changed to allow 0 or more fractional digits (limited to 9 if there must be a limit). The number of digits in the fractional seconds SHOULD be based on the precision of the clock on the computer that ran the tool or performed the conversion. Although the clock may not be accurate to higher precisions, computing durations from clock values measured on the same host is accurate.