https://learn.microsoft.com/en-us/dotnet/api/system.windows.controls.calendar.displaydatestartproperty?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-10.0
Calendar.DisplayDateStartProperty Field (System.Windows.Controls) | Microsoft Learn
Identifies the DisplayDateStart dependency property.
field systemcalendarwindowscontrolsmicrosoft