The Use Date of Markers for Embedded Tokens Minicalendar Modifier, denoted by :dte, is used to tell Q++ to use the baseline date of minicalendar date markers as the reference date for any tokens embedded in the current minicalendar.
Most of the time, using this modifier has no effect, as embedded tokens are evaluated, as usual, assuming that DayValue 1 is the first day of the month of the minicalendar. The only time when the use of this modifier makes a difference is when there is an offset to the beginning of the minicalendar dates, either through the use of starting date offsets, or the use of left and right halves of month modifiers.
Note that the use of this modifier can produce some unexpected results, and is rarely used. If you think that this option might be of use to you in one of your diaries, you should contact technical support and discuss the matter.