$ git clone -n https://src.fedoraproject.org/rpms/rubygem-minitest-stub-const.git /var/lib/mock/f45-build-35095-693/root/chroot_tmpdir/scmroot/rubygem-minitest-stub-const
Cloning into '/var/lib/mock/f45-build-35095-693/root/chroot_tmpdir/scmroot/rubygem-minitest-stub-const'...
$ git fetch origin 2feda47df185cace0cec141881934f7cd7eea2c3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-minitest-stub-const
 * [new ref]         2feda47df185cace0cec141881934f7cd7eea2c3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2feda47 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild