Someone probably returned it, digitec checked that everything was as it should be and found it to be good.
If you are referring to
HTC One M9 (5", 32GB, 20MP, Silver on Gold), you can assume that the phone looks like new, but the seal on the packaging is broken and the USB cable is no longer welded to the original. In short: the product is as good as new and you will (almost certainly) not notice any difference.
See also
https://de.wikipedia.org/wiki...