DTV — rename 'calendar date'

DTV section 12.3.4 defines 'calendar date' as: "Gregorian year month date coordinate or Gregorian day of year coordinate or year weekday coordinate".
This is clearly a definition of 'Gregorian calendar date' or 'Gregorian date'. The general concept 'calendar date' is "absolute time coordinate that indicates a time point that corresponds to exactly one calendar day". The list given in the definition is just the ones defined for Gregorian calendars. The general concept 'calendar date' is useful, and the term should not be assigned to Gregorian dates only. As defined, a 'date time' (date and time) also requires a Gregorian date, but it is not clear that there is a useful generalization.

Recommendation: Rename 'calendar date' to 'Gregorian date' or something the like, and define the general concept 'calendar date' as well.

(All references hereafter are to the Beta-2 specification.)
This resolution addresses the concerns in Issues 16669, 16672, 17429 and 18167, which are interrelated and change the same parts of the specification.
The FTF agrees that the general concept ‘calendar date’ is useful, and that the current concept should be renamed ‘Gregorian date’. Similarly, the term ‘date coordinate’ is generalized, and ‘Gregorian date coordinate’ is added. The generalized definition of ‘calendar date’ takes into account the recommendation in issue 17429 that it refer to absolute time coordinate.
Issue 17429 points out that the definition of ‘calendar date’, now ‘Gregorian date’, confuses ‘Gregorian day of year coordinate’ with ‘Gregorian year day coordinate’, and that is also corrected.
The FTF also determined that the general concept ‘time of day’ goes beyond UTC and its derivatives, and should also be included in Clause 10. Together with 'calendar date', this permits the notion ‘date and time coordinate’ to be generalized and included in Clause 10.
Issue 18167 and Issue 16672 point out that ‘time of day’ and ‘time of day coordinate’ are distinct concepts and need to be properly distinguished in the process of generalization.
Issue 18167 and 16669 point out that the glossary entry for ‘local time’ in clause 10.3 refers to a non-existent term ‘standard time of day’. The term 'local time' is implicitly clarified to mean a kind of 'time point', and the reference to 'standard time of day' is replaced with a reference to the existing term 'standard time'.