$ git clone -n https://src.fedoraproject.org/rpms/R-sessioninfo.git /var/lib/mock/f40-build-1930458-25111/root/chroot_tmpdir/scmroot/R-sessioninfo
Cloning into '/var/lib/mock/f40-build-1930458-25111/root/chroot_tmpdir/scmroot/R-sessioninfo'...
$ git fetch origin 29551165d5b3f6b6522c007533ffedc410120187:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-sessioninfo
 * [new ref]         29551165d5b3f6b6522c007533ffedc410120187 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2955116 R-maint-sig mass rebuild