[FIG(quote)[
[FIGCAPTION[
[1] [CITE@en[ebml-specification/specification.markdown at master · Matroska-Org/ebml-specification]]
([TIME[2017-05-10 14:35:58 +09:00]])
<https://github.com/Matroska-Org/ebml-specification/blob/master/specification.markdown#date-element>
]FIGCAPTION]

> A Date Element MUST declare a length of either zero octets or eight octets. If the EBML Element is not defined to have a default value, then a Date Element with a zero-octet length represents a timestamp of 2001-01-01T00:00:00.000000000 UTC '''['''@!RFC3339''']'''.
> The Date Element stores an integer in the same format as the Signed Integer Element that expresses a point in time referenced in nanoseconds from the precise beginning of the third millennium of the Gregorian Calendar in Coordinated Universal Time (also known as 2001-01-01T00:00:00.000000000 UTC). This provides a possible expression of time from 1708-09-11T00:12:44.854775808 UTC to 2293-04-11T11:47:16.854775807 UTC.

]FIG]


[2] [CITE@en[ebml-specification/specification.markdown at master · ietf-wg-cellar/ebml-specification · GitHub]], [TIME[2026-01-01T11:14:35.000Z]] <https://github.com/ietf-wg-cellar/ebml-specification/blob/master/specification.markdown#date-element>



[3] 
[CITE@en[Date Element specs: fix miscalculation & clarification about leap seconds · Issue #411 · ietf-wg-cellar/ebml-specification]], [TIME[2026-01-01T11:14:51.000Z]] <https://github.com/ietf-wg-cellar/ebml-specification/issues/411>


[4] >>3 [[閏秒]]の規定がなかったため、[[閏秒のないUTC]]と明確化されました。