I want to know the format description of JSON messages sent through HTTPS webhook alert rules

Question

for example,this is the message I received. I want to know the description of the bold field,thank you

    "AGENT":"",
    "BROKER":"Common",
    "CLOSE_TIME":null,
    "COMPANY_ID":"PJZIJ6XV5JQZ2F1QFS6OM5246LYB00U4",
    "COMPONENT":"",
    "COMPONENT_TYPE":"",
    "COMPRESS_KEY":"",
    "COUNTS":1,
    "CREATE_TIME":null,
    "EVENT_ID":"",
    "EVENT_OBJ":"",
    "FIRST_TIME":null,