ENS Web Control blocks file downloads when the URL starts with blob://https. ENS Web Control blocks blob URL file downloads when the ENS Web Control Options policy option "Apply this action to sites not yet verified by McAfee GTI" is set to Block.

A Blob URL/Object URL is a pseudo protocol to allow blob and file objects to be used as a URL source for images and download links for binary data. A Blob URL is not a valid URL format, so Global Threat Intelligence (GTI) can't categorize it.