HipChat integration's callbackUrl not getting called

[foca]

Building a new integration, but I don't get requests to the callbackUrl.

On installation I give it the URL to the add-on/capabilities descriptor, and I see in my logs a GET request to it, but I never see a any requests done against what's defined under `installable.callbackUrl`.

What am I doing wrong?

Here's the JSON I'm providing to HipChat to install (names changed, but the structure is the same):

{
  "name": "Foobar",
  "description": "Lorem ipsum dolor sit amet",
  "key": "com.example.foobar",
  "links": {
    "homepage": "https://foobar.ngrok.io/",
    "self": "https://foobar.ngrok.io/hipchat/install"
  },
  "vendor": {
    "name": "Something or Other",
    "url": "http://foobar.com"
  },
  "installable": {
    "allowGlobal": false,
    "allowRoom": true,
    "callbackUrl": "https://foobar.ngrok.io/hipchat/installed?callback=1"
  },
  "capabilities": {
    "hipchatApiConsumer": {
      "fromName": "Foobar",
      "scopes": [
        "send_notification"
      ]
    },
    "webhook": [
      {
        "name": "Foo the bar",
        "url": "https://foobar.ngrok.io/hipchat/message",
        "event": "room_message",
        "pattern": "^/foo(\\s+.*)?$",
        "authentication": "jwt"
      }
    ]
  }
}

[Gonchik Tsymzhitov]

I think it's obsolete request :(

Because the product is not used anymore, 

So sad to find questions without replies