  The 96.4 day exposure of a 3 kg ultra-low noise germanium detector to the
high flux of antineutrinos from a power nuclear reactor is described. A very
strong preference ($p<1.2\times10^{-3}$) for the presence of a coherent elastic
neutrino-nucleus scattering (CE$\nu$NS) component in the data is found, when
compared to a background-only model. No such effect is visible in 25 days of
operation during reactor outages. The best-fit CE$\nu$NS signal is in good
agreement with expectations based on a recent characterization of germanium
response to sub-keV nuclear recoils. Deviations of order 60\% from the Standard
Model CE$\nu$NS prediction can be excluded using present data. Standing
uncertainties in models of germanium quenching factor, neutrino energy
spectrum, and background are examined.
