$ git clone -n https://src.fedoraproject.org/rpms/R-bindrcpp.git /var/lib/mock/f38-build-724229-99404/root/chroot_tmpdir/scmroot/R-bindrcpp
Cloning into '/var/lib/mock/f38-build-724229-99404/root/chroot_tmpdir/scmroot/R-bindrcpp'...
$ git fetch origin ab4dd62e1254261297bac2b36ebbac89d23162a9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-bindrcpp
 * [new ref]         ab4dd62e1254261297bac2b36ebbac89d23162a9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ab4dd62 R-maint-sig mass rebuild