curl --request GET \
  --url https://api.hubapi.com/events/v3/event-definitions/{eventName} \
  --header 'Authorization: Bearer <token>'

{
  "associations": [
    {
      "inverseLabel": "",
      "hidden": false,
      "allowsCustomLabels": false,
      "maxFromObjectIds": 123,
      "inverseAllowsCustomLabels": false,
      "isPrimary": false,
      "hasUserEnforcedMaxToObjectIds": false,
      "hasUserEnforcedMaxFromObjectIds": false,
      "id": 123,
      "toObjectTypeId": "",
      "inverseCardinality": "",
      "maxToObjectIds": 123,
      "hasCascadingDeletes": false,
      "fromObjectType": "",
      "toObjectType": "",
      "label": "",
      "inverseId": 123,
      "cardinality": "",
      "inverseName": "",
      "hasAllAssociatedObjects": false,
      "inverseHasAllAssociatedObjects": false,
      "fromObjectTypeId": "",
      "portalUniqueIdentifier": "",
      "isInversePrimary": false,
      "name": "",
      "category": ""
    }
  ],
  "objectTypeId": "<string>",
  "createdUserId": 123,
  "trackingType": "VISITED_URL",
  "description": "<string>",
  "primaryObjectId": "<string>",
  "comboEventRules": {
    "operationType": "AND",
    "composingRules": [
      {
        "lookbackWindowDays": 123,
        "eventTypeId": "<string>",
        "propertyFilters": [
          {
            "frameworkFilterId": 123,
            "property": "<string>",
            "filterType": "PROPERTY",
            "operation": {
              "includeObjectsWithNoValueSet": true,
              "defaultValue": "<string>",
              "propertyType": "bool",
              "operationType": "<string>",
              "value": true,
              "operatorName": "<string>",
              "operator": "IS_EQUAL_TO"
            }
          }
        ],
        "count": 123
      }
    ],
    "ruleBranches": [
      {}
    ]
  },
  "fullyQualifiedName": "<string>",
  "primaryObject": "<string>",
  "labels": {
    "plural": "<string>",
    "singular": "<string>"
  },
  "archived": true,
  "createdAt": "2023-11-07T05:31:56Z",
  "name": "<string>",
  "id": "<string>",
  "properties": [
    {
      "hidden": false,
      "displayOrder": 123,
      "description": "",
      "showCurrencySymbol": false,
      "type": "",
      "hubspotDefined": false,
      "createdAt": "2023-11-07T05:31:56Z",
      "archived": false,
      "options": "",
      "hasUniqueValue": false,
      "calculated": false,
      "externalOptions": false,
      "updatedAt": "2023-11-07T05:31:56Z",
      "createdUserId": "",
      "modificationMetadata": {
        "readOnlyOptions": true,
        "readOnlyValue": true,
        "readOnlyDefinition": true,
        "archivable": true
      },
      "sensitiveDataCategories": "",
      "label": "",
      "formField": false,
      "dataSensitivity": "",
      "archivedAt": "2023-11-07T05:31:56Z",
      "groupName": "",
      "referencedObjectType": "",
      "name": "",
      "calculationFormula": "",
      "fieldType": "",
      "updatedUserId": "<string>"
    }
  ]
}