There are quite few discussions (back to 2020) dealing with the variable max_day_to_hold and the (non-) handling of the set value, I found for example Marc's comment https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/message/... :

I'm really not sure what you are looking to do, but I can tell you that while the max_days_to_hold list attribute exists and can be set, the actual discarding of held messages older than max_days_to_hold is not implemented. Thus the setting currently does nothing.

My question:

Are there any plans to bring this into action, so that held messages are really discarded after that number of days? (like it was in mailman2)?