  We present gyrokinetic simulations with the GENE code addressing the
near-edge region of an L-mode plasma in the DIII-D tokamak. At radial position
$\rho=0.80$, simulations with the ion temperature gradient increased by $40\%$
above the nominal value give electron and ion heat fluxes that are in
simultaneous agreement with the experiment. This gradient increase is
consistent with the combined statistical and systematic uncertainty $\sigma$ of
the Charge Exchange Recombination Spectroscopy (CER) measurements at the $1.6
\sigma$ level. Multi-scale simulations are carried out with realistic mass
ratio and geometry for the first time in the near-edge. These multi-scale
simulations suggest that the highly unstable ion temperature gradient (ITG)
modes of the flux-matched ion-scale simulations suppress electron-scale
transport, such that ion-scale simulations are sufficient at this location. At
radial position $\rho=0.90$, nonlinear simulations show a hybrid state of ITG
and trapped electron modes~(TEMs), which was not expected from linear
simulations. The nonlinear simulations reproduce the total experimental heat
flux with the inclusion of $\mathbf{E} \times \mathbf{B}$ shear effects and an
increase in the electron temperature gradient by $\sim 23\%$. This gradient
increase is compatible with the combined statistical and systematic uncertainty
of the Thomson scattering data at the $1.3 \sigma$ level. These results are
consistent with previous findings that gyrokinetic simulations are able to
reproduce the experimental heat fluxes by varying input parameters close to
their experimental uncertainties, pushing the validation frontier closer to the
edge region.
