upload authorization. More examples, fix some typo

buds/06.md

@@ -19,6 +19,12 @@ The `HEAD /upload` endpoint `MUST` use the `Content-Digest`, `X-Content-Type` an
 - `X-Content-Type`: A string that specifies the fblobile's MIME type, like `application/pdf` or `image/png`.
 - `X-Upload-Message`: A human readable message that explains the reason why the upload cannot proceed.
 
+### Upload Authorization  
+
+The `HEAD /upload` endpoint MAY accept an `upload` authorization event using the `Authorization` header similar to what is used in the [`PUT /upload`](./02.md#upload-authorization-required) endpoint  
+
+If the server requires authorization to upload it may respond with the `401` status code, or if authorization was provided and is invalid or not permitted it may respond with `403` status code  
+
 ### Examples
 
 Example request from the client:
@@ -35,7 +41,8 @@ Example response from the server if the upload can be done:
 HTTP/1.1 200 OK
 ```
 
-If the upload cannot proceed, the server `MUST` return an appropriate HTTP status code and a custom header `X-Upload-Message` with a human readable error message.
+If the upload cannot proceed, the server `MUST` return an appropriate `4xx` HTTP status code and a custom header `X-Upload-Message` with a human readable error message.  
+
 
 Some examples of error messages:
 
@@ -44,6 +51,21 @@ HTTP/1.1 400 Bad Request
 X-Upload-Message: Invalid Content-Digest header format. Expected format: sha-256=:<hash>:
 ```
 
+```http
+HTTP/1.1 401 Unauthorized  
+X-Upload-Message: Authorization required for uploading video files
+```
+
+```http
+HTTP/1.1 401 Forbidden  
+X-Upload-Message: Account banned
+```
+
+```http
+HTTP/1.1 411 Length Required  
+X-Upload-Message: Missing Content-Length or X-Content-Length headers
+```
+
 ```http
 HTTP/1.1 413 Content Too Large
 X-Upload-Message: File too large. Max allowed size is 100MB