on overdues.pl, we have an 'email' link next to each overdue, this link is a mailto link with the borrower's email as recipient and OVERDUE : [book title] as the subject. Unfortunately this string cannot be picked up by the translation tools. There used to be a manual overdue notice, which filled this mailto link according to what the library wanted, which would handle this problem.
*** This bug has been marked as a duplicate of bug 8330 ***