if we enable a secondary calendar a tooltip that shows the date in that calendar will be available inside the calendar, I mean when we hover over a date inside the calendar. also there is a log format of current date in secondary calendar format, in the agenda subtitle(as shown in in the screenshot bellow).
but there should be a posseblity for tooltip to show date in secondary calendar when we hover over the clock plus it would be very useful if we could have a chance to enter a custom date format in order to have date in secondary calendar beside/bellow the click.(currently it only accepts qt.date format string and date is in Gregorian)  
also it would be easier to add a second text box to specify the locale format and then using JS `Date().toLocaleDateString()` which will enable user to have more control on what he want to see, e.g: `new Date().toLocaleDateString('fa-IR',{year:'numeric',month:'2-digit',day:'2-digit',formatMatcher:'basic'})`

![Screenshot_20230517_112017](/uploads/df633fbb59092ab70be20c08eeba9909/Screenshot_20230517_112017.png)
![Screenshot_20230517_111101](/uploads/dddc449f4abccf39e7ac5a019fc52fa5/Screenshot_20230517_111101.png)