This is a linked open data (LOD) about date and time. "28 טבת 5781" is a date of Hebrew Calendar-TEST (Calendar ID: 104.1).
http://datetime.hutime.org/calendar/104.1/date/28_טבת_5781
hcal:104.1/date/2459226.5
hcal:104.1/date/28_טבת_5781
hcaldate:2459226.5
hcaldate:28_טבת_5781