Opening file from iCloud Desktop versus Mail attachment

Am developing an iOS App, which uses a ZipFoundation wrapper around Compression. In XCode, have exported a document type with extension '.MU' in the Info.plist.

On iPhone, when attempting to open archive called: 'Snapshot-test.mu' can OPEN as a mobile email attachment but FAILED via Files App referring to "iCloud Drive/Desktop"

Here are the respective URLS

"file:///private/var/mobile/Containers/Data/Application/<UniqueID>/Documents/Inbox/Snapshot-test.mu"	

"file:///private/var/mobile/Library/Mobile%20Documents/com~apple~CloudDocs/Desktop/Snapshot-test1.mu"	

Two questions:

  1. Is it possible to grant access to files residing remotely in iCloud?
  2. Is "iCloud Drive/Desktop" unique, whereas other iCloud locations would be OK?
Opening file from iCloud Desktop versus Mail attachment
 
 
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