[1] Organization Webhooks | GitHub API (2015-02-19 00:56:09 +09:00 版) https://developer.github.com/v3/orgs/hooks/

The Organization Webhooks API is currently available for developers to preview. During the preview period, the API may change without advance notice. Please see the blog post for full details.
To access the API during the preview period, you must provide a custom media type in the Accept header:
application/vnd.github.sersi-preview+json