I did a quick search, and I've only seen this brought up indirectly.
In the reconciliation interface, transactions dated up to a week after the end date should be available for being reconciled.
The use case is pretty simple... many times, transactions on one statement don't have the same date as the method of adding to Books, whether that's importing or using feeds.
A specific example would be someone using their bank feed to enter transactions. A merchant account may have sent a payment on 31 May 2021, but did not get deposited into the user's bank account until 3 June 2021. If the transaction is created from the bank account feed, it's dated as 3 June 2021 in both places.
This creates a problem when reconciling the merchant services statement. If the reconciliation is correctly dated to end on 31 May 2021 like the statement, the transaction is not available for reconciliation.
I am aware that there are workarounds, but this really should be solved at the software level. Just like unreconciled transactions dated prior to the start date are available for reconciliation, so should some transactions that are dated in the books to be after the reconcilation end date.