In step 1, we see the basic command that we're using as a CLI operator.
In step 2, the extra output pipe causes the JUNOS OS management daemon to not actually execute the command, but instead tell us the RPC that it would use if it were executing the command. So, in this case, we can see that it's <get-arp-table-information>, which is the focus of our attention.
In step 3, we get to learn what the likely response from this RPC will be when our automation app makes the RPC call. In this case, the normal tabular format seen by the human is presented to a machine reader, with each of the fields decorated by XML tags. This allows easy and unambiguous interpretation of the response.