This endpoint allows you to get a registered webhook.
{
"id":"1",
"resource": "channel_inventory",
"eventType": "POST",
"eventSubType": "updated",
"version": "v1",
"externalChannelID" : "CLARKS",
"webhookUrl": "https://hooks.zapier.com/fake-subscription-url",
"webhookMethod": "POST",
"createdAt": "2020-02-27T18:32:15.528+05:30",
"updatedAt": "2020-02-27T18:32:15.528+05:30"
}