Current options are

• %1 = The day number of the period posting date
• %2 = The week number of the period posting date
• %3 = The month number of the period posting date
• %4 = The month name of the period posting date
• %5 = The accounting period name of the period posting date
• %6 = The fiscal year of the period posting date

It would be great if you could use the description of the line

eg: %7 = The line description of the item

%7 %4 %6 would then give "line description expense for May 2025" for example. You might need to trim the contents of the line desc to show the period and year, but it would be better than some generic description defined on the deferral template.