When releasing a private address, there is now an option to “empty the inbox” – deleting all messages associated with the private address. You can find the option by clicking the settings button when managing your private addresses.
The API endpoint DELETE /api/addresses/:email now supports the query string deleteAddressMessages. When deleteAddressMessages=true is passed, all messages associated with the inbox will be deleted.
Please note that all messages are deleted, including starred/saved messages. It is immediate and irreversible.