$ git clone -n https://src.fedoraproject.org/rpms/R-covr.git /var/lib/mock/f42-build-side-1-3499347-45964/root/chroot_tmpdir/scmroot/R-covr
Cloning into '/var/lib/mock/f42-build-side-1-3499347-45964/root/chroot_tmpdir/scmroot/R-covr'...
$ git fetch origin 1a9d4c5bcd80518f0d961581907d976033ad4689:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-covr
 * [new ref]         1a9d4c5bcd80518f0d961581907d976033ad4689 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1a9d4c5 R-maint-sig mass rebuild