$ git clone -n https://src.fedoraproject.org/rpms/libisoburn.git /var/lib/mock/f41-build-750638-13382/root/chroot_tmpdir/scmroot/libisoburn
Cloning into '/var/lib/mock/f41-build-750638-13382/root/chroot_tmpdir/scmroot/libisoburn'...
$ git fetch origin 51d4512e388a3dd369d673c086a7483d022015fc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libisoburn
 * [new ref]         51d4512e388a3dd369d673c086a7483d022015fc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 51d4512 Spec file cleanup, modernization and unification...