$ git clone -n https://src.fedoraproject.org/rpms/fedora-bookmarks.git /var/lib/mock/f45-build-8843-396/root/chroot_tmpdir/scmroot/fedora-bookmarks
Cloning into '/var/lib/mock/f45-build-8843-396/root/chroot_tmpdir/scmroot/fedora-bookmarks'...
$ git fetch origin cfceba94db3ddb72a5980889ae77b2a269dee3a1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-bookmarks
 * [new ref]         cfceba94db3ddb72a5980889ae77b2a269dee3a1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cfceba9 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild