$ git clone -n https://src.fedoraproject.org/rpms/R-testit.git /var/lib/mock/f42-build-side-1-3502106-45977/root/chroot_tmpdir/scmroot/R-testit
Cloning into '/var/lib/mock/f42-build-side-1-3502106-45977/root/chroot_tmpdir/scmroot/R-testit'...
$ git fetch origin 22c8383388c0362e0295577c61c105c15fbd176e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-testit
 * [new ref]         22c8383388c0362e0295577c61c105c15fbd176e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 22c8383 R-maint-sig mass rebuild