Alright, I found the answer. In the end I found the link by opening the link in the command,
click the "Repositories" tab click the "Go to download repository" link under my version of openSUSE (openSUSE_Leap_42.1 for me)
There the file is listed. Click on the file and then copy the link from the browser address bar and run it with zypper ar
. For me it turned out to be:
zypper ar http://download.opensuse.org/repositories/isv:/ownCloud:/toolchains:/mingw:/win32:/stable/openSUSE_Leap_42.1/isv:ownCloud:toolchains:mingw:win32:stable.repo
I hope this someday helps someone else with the same problem