$ git clone -n https://src.fedoraproject.org/rpms/libgexiv2.git /var/lib/mock/f42-build-side-1-3534292-46548/root/chroot_tmpdir/scmroot/libgexiv2
Cloning into '/var/lib/mock/f42-build-side-1-3534292-46548/root/chroot_tmpdir/scmroot/libgexiv2'...
$ git fetch origin 71a2a021354293aac2a1a14ce7edbef9c51dde6e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libgexiv2
 * [new ref]         71a2a021354293aac2a1a14ce7edbef9c51dde6e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 71a2a02 Update to 0.14.5