That's the trouble: Prior to the Dingo release, borrowed books sideloaded onto the eDGe used to display (on their icon) a diagonal, blue banner once added to the library. The banner indicated the number of days left on the loan, for example, "21 days." Also, if you long-pressed on the book icon, one of the navigation options was "Return," after which, you'd get a prompt warning you that if you returned the book, you'd no longer have access to it.
That functionality appears to be gone.
It's too bad. I really liked being able to distinguish borrowed books from the others on sight and being able to return them--early, if I wanted.