$ git clone -n https://src.fedoraproject.org/rpms/R-usethis.git /var/lib/mock/f38-build-side-42-init-devel-1392157-30890/root/chroot_tmpdir/scmroot/R-usethis
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1392157-30890/root/chroot_tmpdir/scmroot/R-usethis'...
$ git fetch origin 9655a0d54e0bb5aae7a3f023d5af11c18b02652f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-usethis
 * [new ref]         9655a0d54e0bb5aae7a3f023d5af11c18b02652f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9655a0d R-maint-sig mass rebuild