that is a broadcast trace. it show the broadcast came from the bridged lan port eth0 and was sent out the bridged lan port ath0 (wireless) from source IP 192.168.88.1 to all/any device.
depending on your logging level and setup, these are common since the IP protocol uses ARP to locate IP to MAC addresses.
So without knowing a lot more about your network design and how your network operates, this is just a broadcast packet from your network to the SMs.