Hi there @source232, thanks for reaching out to us here!
At the moment, .bkp are not a file type that can be previewed through Dropbox. You can check out a list of supported file types from here.
Since the file can't be previewed through Dropbox, you would view the file locally on your device where you have the appropriate app that can open/view this file type.
I hope this helps, let me know if you have any questions!
Daphne
Community Moderator @ Dropbox
dropbox.com/support
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Happy to be of help @source232!
I'm just a post away if you have any other questions. 
Have a great weekend Dan!
Daphne
Community Moderator @ Dropbox
dropbox.com/support
Did this post help you? If so, please give it a Like below. Still stuck? Ask me a question! Tips & Tricks Find new ways to stay in flow or share your tips on how you work smarter with Dropbox.
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