[LEAPSECS] Leap second relationship to ISO 8601

[Gerard Ashton]

ISO 8601 is expensive; I obtained a copy before they started making it hard
to find copies on the web. The wording of the standard is convoluted. Does
anyone know if there is a highly-reputable, readable description of the
standard that explains the extent to which the various choices are required,
recommended, or merely allowed?

For example, if one wishes to use the format 2014-08-24, is it mandatory
that the day begin at midnight according to some unspecified local time?

If one wishes to specify the time, does the standard recommend 23:02Z over
07:03, or are they on an equal footing?

Is there a highly respected discussion anywhere of what to do about UTC
before leap seconds, or the period before the introduction of UTC, in ISO
8601 representations?

Gerry Ashton