According to https://help.shopify.com/en/api/guides/billing-api#webhooks-for-billing we can use webhooks to act on app subscription related events.
But I can't find anything regarding the request body. It's also not an easy webhook to trigger. Takes a lot of steps to unsubscribe and resubscribe just to fire this topic.
Can one of the Shopify devs at least post a snippet of an example here, before the official docs are updated? Thanks.