Maximum time-to-live (TTL) of WNS push service?

Question

I'm currently testing some examples of web push, and I have a question about WNS push service.

As far as I know, when I request to send a push event to push services, I can specify required TTL at request header. If TTL exceeds push services own limit, they adjust the TTL and respond with actual TTL they applied.

So, I expect if I put pretty large number for TTL, such as 1234567890, the response would tell me the maximum TTL of each push service.

But only mozilla push service responds with maximum TTL, which is "ttl": "5184000" and others like FCM, WNS didn't respond with adjusted TTL.

I tried to find maximum TTL of FCM and WNS on the docs, and it seems FCM's maximum TTL is 28 days. But I couldn't find WNS's maximum TTL.

Does anyone knows what is the maximum TTL of WNS push service?

This is simplified test code I'm currently using. (js)

const webpush = require("web-push");
webpush
  .sendNotification(subscription, "TTL test", {
    TTL: 1234567890,
  })
  .then((res) => console.log(`${JSON.stringify(res)}`))
  .catch((res) => {
    console.log(`${JSON.stringify(res)}`);
  });