$ git clone -n https://src.fedoraproject.org/rpms/R-R.utils.git /var/lib/mock/f43-build-side-110352-58908784-6569187/root/chroot_tmpdir/scmroot/R-R.utils
Cloning into '/var/lib/mock/f43-build-side-110352-58908784-6569187/root/chroot_tmpdir/scmroot/R-R.utils'...
$ git fetch origin d2ed7930e6c66ae0976e560ca854ef7a6fca7fe5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-R.utils
 * [new ref]         d2ed7930e6c66ae0976e560ca854ef7a6fca7fe5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d2ed793 R-maint-sig mass rebuild