For mobile passes, a travel runs from 0:00 until 23:59 CET, as is mentioned on this page and this page. However, what happens during daylight savings time? If we take the text on these pages literally, then during daylight savings time, a travel day also runs from 0:00 until 23:59 CET, which is 1:00 until 0:59 CEST.
I suspect that during daylight savings time, a travel day runs from 0:00 until 23:59 CEST. If that is indeed the case, then I think it's a good idea to state that explicitly on the pages mentioned.