From GovExec.com
https://www.govexec.com/

In a surprise move, President Trump on Tuesday signed an executive granting most federal employees an extra day off on Christmas Eve:
“All executive departments and agencies of the Federal Government shall be closed and their employees excused from duty on Tuesday, December 24, 2019, the day before Christmas Day.”
It was a gift few expected. Presidents do not typically grant extra vacation time when Christmas falls on a Wednesday.

Margaret Weichert, deputy director for management at the White House Office of Management and Budget, told an audience of senior executives Tuesday evening that President Franklin Roosevelt was the last president to give federal employees the day off when Christmas Eve fell on a Tuesday.

https://www.govexec.com/pay-benefits...as-eve/161974/