If you host you own files you should be able to control whatever headers you need. If you are using the Akamai to host your files it is unlikely changes would be made as it would impact all customers.

This was recently answered by Jeffrey Walter on the Launch Developers slack channel (launch-developers.slack.com) I'll summarize here:Launch provides the ability to establish callbacks (Webhooks) that will be POSTED to when a subscribed audit event happens. An Audit event is described as [resource]:[action] using the resources and actions shown below.Subscriptions for callbacks are set up using the Launch API as shown here: Launch Callbacks via API