Webhook & authentication via POST

I’m trying to get informations from grafana webhook in php.
I can get the json via file_get_contents(‘php://input’)
BUT, where are located the username & password grafana is asking us for the webhook ?
Is it a header in the post ?
Is it a cookie header ?
Is it something else ?

I’m replying to myself:
It’s only basic auth and in php you need to use _SERVER['PHP_AUTH_USER'] and _SERVER[‘PHP_AUTH_PW’] to get username and password send by the webhook