This is a linked open data (LOD) about date and time. "C.E. 2020 September 16" is a date of Gregorian Calendar (Calendar ID: 2.1).
http://datetime.hutime.org/calendar/2.1/date/C.E._2020_September_16
hcal:2.1/date/2459108.5
hcal:2.1/date/C.E._2020_September_16
hcaldate:2459108.5
hcaldate:C.E._2020_September_16