Check /etc/zypp/repos.d for the current repository definitions. The repository prefixed with openSUSE: are automatically installed by repository service. What you can do is
Copy (or rename) repository definitions starting with openSUSE: - just strip off prefix
That was a learning experience for me. Looking back at zypper’s logs now, the mirror list that zypper got from http://download.opensuse.org/update/slowroll/repo/oss?mirrorlist (below) was different from the …/repodata/?mirrorlist I posted here back on 13 Jun. At the time, I just got spooked because I had noticed that zypper was not using one of those mirrors.
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(RepoMirrorListParse):289 Parsing mirrorlist file: /var/tmp/TmpFile.Yqbz26 originally received from http://download.opensuse.org/update/slowroll/repo/oss?mirrorlist
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(detectRepoMirrorListFormat):133 Detecting RepoMirrorlist Format based on file content
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(detectRepoMirrorListFormat):162 Detected JSON, file starts with [
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://ftp.belnet.be/mirror/ftp.opensuse.org/opensuse/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://mirror.nl.leaseweb.net/opensuse/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://opensuse.mirror.liteserver.nl/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://opensuse.mirror.liteserver.nl/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://ftp.halifax.rwth-aachen.de/opensuse/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://ftp.uni-kl.de/pub/linux/opensuse/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://mirror.de.leaseweb.net/opensuse/update/slowroll/repo/oss/
2025-06-13 06:11:54 <1> persephone(4267) [zypp::media] RepoMirrorList.cc(operator()):224 Trying to parse URL: http://ftp.tu-chemnitz.de/pub/linux/opensuse/update/slowroll/repo/oss/