$ git clone -n http://fedora.riscv.rocks:3000/rpms/R-packrat.git /var/lib/mock/f41-build-838724-159756/root/chroot_tmpdir/scmroot/R-packrat
Cloning into '/var/lib/mock/f41-build-838724-159756/root/chroot_tmpdir/scmroot/R-packrat'...
$ git fetch origin c26b62101faf7e179026ed3d9e81d884622f1972:KOJI_FETCH_HEAD
From http://fedora.riscv.rocks:3000/rpms/R-packrat
 * [new ref]         c26b62101faf7e179026ed3d9e81d884622f1972 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c26b621 Enable bootstrap