There is no documentation for receiving opt-out from Marketing messages in these 2 links provided.

https://developers.facebook.com/docs/messenger-platform/marketing-messages https://developers.facebook.com/docs/messenger-platform/webhooks

Anyone knows how to test them? When we clicked on Opt-out link through a Meta App that is in development mode - we didn't receive any webhooks. There is no tool to send a test webhook for opt-out under the Meta App's webhook section as well.