What are the purposes of $property_map.input and $property_map.output in a *.slp file

I have downloaded a pipeline as a *.slp file and opened it in a text editor. Noticed that both $property_map.input and $property_map.output refer certain snaps in the pipeline. What’s purpose of following two objects:

• $property_map.input
• $property_map.output

Why are those snaps singled out, for example “Mapper_FailedCertificatesList - output0”?

Following is the snippet:

  "property_map": {
    "info": null, 
    "input": {
      "7536ff22-1c0d-44c6-ada7-718de5a98634_input0": {
        "label": {
          "value": "Conditional_Certificates_Offers_Length - input0"
        },
        "view_type": {
          "value": "document"
        }
      }
    },
    "settings": {
      "param_table": {
        "value": 
      },
      "imports": {
        "value": []
      }
    },
    "output": {
      "ac14846d-7856-4e1d-9ca0-b519741a25b6_output0": {
        "view_type": {
          "value": "document"
        },
        "label": {
          "value": "Error 400 Union - output0"
        }
      },
      "2bfe809b-a4b7-4f9b-9007-5262ea6b0b58_output0": {
        "label": {
          "value": "Mapper_FailedCertificatesList - output0"
        },
        "view_type": {
          "value": "document"
        }
      },
      "36e341cd-bb8d-42d9-94f9-24eb72a812c8_output0": {
        "view_type": {
          "value": "document"
        },
        "label": {
          "value": "Mapper_FailedCertificatesList - output0"
        }
      }
    },

I do noticed that snap “Mapper_FailedCertificatesList - output0” has io_stats object has value while most other snap don’t in the pipeline monitor API output. Here’s an example of the io_stats value:

[
  {
    "send_duration": 49923,
    "remote": "pa23sl-fmsv-ux02007.fsac5.snaplogic.net/172.29.66.28:8089",
    "bytes_recv": 0,
    "start_time": 1499885665780,
    "error_duration": 0,
    "bytes_sent": 1370,
    "recv_duration": 0,
    "error_count": 0,
    "type": "socket"
  },
  {
    "send_duration": 149004,
    "remote": "pa23sl-fmsv-ux02000.fsac5.snaplogic.net/172.29.65.214:8089",
    "bytes_recv": 0,
    "start_time": 1499885663392,
    "error_duration": 0,
    "bytes_sent": 1178,
    "recv_duration": 0,
    "error_count": 0,
    "type": "socket"
  }
]

This behavior can be seen in SnapRuntimeFlashlight-AllSnaps-RedeemV2.2.xlsx (80.0 KB). It is an aggregated view of the pipeline monitor api output of many ruuids for the same pipeline.

Also attached the .slp file
Redeem_Pl_V2.2_2017_07_12.slp.txt (212.8 KB)

P.S. after post this, saw this in dashboard: and now reading https://doc.snaplogic.com/wiki/display/SD/Check+Pipeline+Execution+Statistics