How do I open .icloud files?

I'm saving data to iCloud in my app using iCloud Documents capability, however I'm not using the Documents folder, instead I'm hiding my files in another folder i.e. User'siCloudContainer/MyFolder.

I've uploaded some .plist files to this folder but when I receive them using another device they've been given a .icloud extension. What does this mean and how can I get my original .plist files?

EDIT: It seems that these files have been wrapped by NSFileWrapper during cloud synchronisation.

The answer as I have now discovered is that .icloud files are the metadata that precedes the full file being downloaded to a device.

From what I can gather, iCloud Drive doesn't want you to create your own hierarchy & drop files where you like, it appears you're supposed to put them in pre-defined locations...

This was the best layman's explanation I could find as to how it works; I'm not a dev, so the details would need filling in by someone with more knowledge than me.
iCloud Drive and Document Picker for iOS 8: Explained