The comment above says:
    # See "Date Time String Format" in the ECMA-262 specification.

ECMA-262 specification explicitly defines that:
```
ECMAScript defines a string interchange format for date-times based upon a simplification of the ISO 8601 Extended Format. The format is as follows: YYYY-MM-DDTHH:mm:ss.sssZ

sss	is the number of complete milliseconds since the start of the second as three decimal digits.

Z	is the time zone offset specified as “Z” (for UTC) or either “+” or “-” followed by a time expression HH:mm
```
This change breaks the specification. reading it back from JS using Date.parse() will anyway trim this


Why this fix is here, does it fix an issue ?