What is the “Junk\ mailbox?
The Junk mailbox (parameter rc_junKMailbox in your .askrc file) receives all messages that came from one of your addresses (rc_mymails) but did not contain your mail key. See the question above regarding the need of a mailkey. ASK 2.3 on operates on a different principle: These messages are not sent to the junk folder anymore. Instead, they’re queued with the X-ASK-Info header set to “Junk”.