I don't see how they can legally have any control over what a 3rd party's software outputs. And more importantly, how would they even enforce such restrictions?
my guess is because it's "X-Elastic-Product" you'd be falsely "saying" your product is made by Elastic, the company so they could sue over it.
Such a concern seems utterly ridiculous.
https://stackoverflow.com/questions/1114254/why-do-all-brows...