$ git clone -n https://src.fedoraproject.org/rpms/R-repr.git /var/lib/mock/f45-build-6366-348/root/chroot_tmpdir/scmroot/R-repr
Cloning into '/var/lib/mock/f45-build-6366-348/root/chroot_tmpdir/scmroot/R-repr'...
$ git fetch origin 3d26cc59662c66519b6e47f884d588e68aa5df2b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-repr
 * [new ref]         3d26cc59662c66519b6e47f884d588e68aa5df2b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3d26cc5 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild