$ git clone -n https://src.fedoraproject.org/rpms/libisoburn.git /var/lib/mock/f45-build-16380-486/root/chroot_tmpdir/scmroot/libisoburn
Cloning into '/var/lib/mock/f45-build-16380-486/root/chroot_tmpdir/scmroot/libisoburn'...
$ git fetch origin 74c3acfc8d256706c901826a65ebb0412b1d71d7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libisoburn
 * [new ref]         74c3acfc8d256706c901826a65ebb0412b1d71d7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 74c3acf Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild