In the absence of a response to bug 425505 I wrote to the e-mail address that is given in the extension: Kai Uwe Broulik <kde@prviat.broulik.de> Delivery failed: > 550 kde@prviat.broulik.de That recipient is not allowed
After updating the extension (not knowing what might change) I found Kai Uwe Broulik <kde@prviat.broulik.de> no longer mentioned.