$ git clone -n https://src.fedoraproject.org/rpms/icestorm.git /var/lib/mock/f42-build-side-1-3587360-46931/root/chroot_tmpdir/scmroot/icestorm
Cloning into '/var/lib/mock/f42-build-side-1-3587360-46931/root/chroot_tmpdir/scmroot/icestorm'...
$ git fetch origin a230c88c5772c38443a3ecd5733b9f685fa6dfb0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/icestorm
 * [new ref]         a230c88c5772c38443a3ecd5733b9f685fa6dfb0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a230c88 update to newer snapshot