Why is Dropbox listed in iCloud Drive settings?

[muchospanish]

On my iPad under Settings > iCloud > iCloud Drive, I have Dropbox listed and turned on. Isn't this a competitive product? Why are they together?

 

[Just_Me_D]

Any app you have installed on your device that supports iCloud storage/sharing will be listed in that section of the settings. Yes, it is a competitive product...