How to add a character on the day of the week

[YAKO SOMEDAKY]

I would like to know if they could help me find where the calendar weekdays display is, as I would like to change the display from 2 characters to 3.
For example: Let's say I want to change the display from Mo to Mon to the Second for example ... of course I want to do this every day of the week, but I do not know where to make that change.

[Andraax]

CoreRPG/utility/scripts/calendar_period_list.lua

function buildCalendarWindows

[YAKO SOMEDAKY]

Thanks Andraax
Attachment 16212