Content-Length in Access-Control-Expose-Headers on public.db.files.1drv.com
The content-length header is missing in the Access-Control-Expose-Headers list for requests made to public.db.files.1drv.com.
This means it is not possible to send HEAD requests for the content length before sending get requests with the Range header.
Oftentimes you would like to retrieve only a portion of a file, containing f.x. headers or metadata at the end of a file. This can only be done if you know the file length beforehand.