https://developer.atlassian.com/server/jira/platform/webhooks/ 

Restricting your events to a subset of issues using JQL is not clearly tied to issues related webhooks. Project-Related and User-Related directions are mentioned between the JQL instructions and Registering events for Issue related events. It would help improve clarity to nest the steps to restrict events to a subset of issues with JQL under the steps for registering Issue related events. Clearly stating that JQL can only restrict Issue related events within this section of the documentation would also help avoid confusion.