$ git clone -n https://src.fedoraproject.org/rpms/R-stringr.git /var/lib/mock/f38-build-side-42-init-devel-929333-28746/root/chroot_tmpdir/scmroot/R-stringr
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-929333-28746/root/chroot_tmpdir/scmroot/R-stringr'...
$ git fetch origin 1ddf7cb28a97795e237493449303a56b40944aee:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-stringr
 * [new ref]         1ddf7cb28a97795e237493449303a56b40944aee -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1ddf7cb Update to latest version (#2120020)