Read Authorization Header in SA

Hi.
I have create a simple server action which returns a file.
I am calling this via Postman with custom Authorization header. But, in the SA, I can’t seem to find how to read this Authorization header.
I tried using $_HEADER & $_SERVER objects, but neither of them are showing this header.
If I add header with any other name, I can see that in both the objects.

Request:

Response:

Is this a bug or am I looking for it in an incorrect place? Please help.