How can I debug OPNsense packet processing?

[skatopn]

I can run a packet capture in OPNsense, but in between the Rx (INGRESS) of a packet on an interface and the Tx (EGRESS) of a packet (assuming it passes all policies) the OPNsense obviously processes a packet through the various configured policies and filters.

Question:
How do I debug packet process within the OPNsense OS to trace the path of the packet from INGRESS (Rx) through to EGRESS (Tx) or denial/dropping?

Note, this is in addition to checking things like ARP cache, DNS cache and other standard diagnostic checks.
What I want to do does not appear to be available in the GUI so I want to know what commands I can use in the CLI to debug packet flow/processing.

TIA