Looks good--I'd suggest just making it a bullet list as it was a bit hard to scan:

Webhooks can be delivered using different content types: 

* The `application/json` content type delivers the JSON payload directly as the body of the POST.
* The `application/x-www-form-urlencoded` content type sends the JSON payload as a form parameter called "payload".

Also, we end with:

> the default content type is fine.

Which of the two is the default content type?