  We present the most extensive catalog of exposures of volatiles on the
67P/Churyumov-Gerasimenko nucleus generated from observations acquired with the
OSIRIS cameras on board the Rosetta mission. We identified more than 600
volatile exposures on the comet. Bright spots are found isolated on the nucleus
or grouped in clusters, usually at the bottom of cliffs, and most of them are
small, typically a few square meters or smaller. Several of them are clearly
correlated with the cometary activity. We note a number of peculiar exposures
of volatiles with negative spectral slope values in the high-resolution
post-perihelion images, which we interpret as the presence of large ice grains
($>$ 1000 $\mu$m) or local frosts condensation. We observe a clear difference
both in the spectral slope and in the area distributions of the bright spots
pre- and post-perihelion, with these last having lower average spectral slope
values and a smaller size, with a median surface of 0.7 m$^2$, even if the size
difference is mainly due to the higher resolution achieved post-perihelion. The
minimum duration of the bright spots shows three clusters: an area-independent
cluster dominated by short-lifetime frosts; an area-independent cluster with
lifetime of 0.5--2 days, probably associated with the seasonal fallout of
dehydrated chunks; and an area-dependent cluster with lifetime longer than 2
days consistent with water-driven erosion of the nucleus. Even if numerous
bright spots are detected, the total surface of exposed water ice is less than
0.1% of the total 67P nucleus surface, confirming that the 67P surface is
dominated by refractory dark terrains, while exposed ice occupies only a tiny
fraction. Moreover, the abundance of volatile exposures is six times less in
the small lobe than in the big lobe, adding additional evidence to the
hypothesis that comet 67P is composed of two distinct bodies.
