Sentinel-2 MSI: MultiSpectral Instrument, Level-2A (COPERNICUS/S2_SR)

Sentinel-2 is a wide-swath, high-resolution, multi-spectral
imaging mission supporting Copernicus Land Monitoring studies,
including the monitoring of vegetation, soil and water cover,
as well as observation of inland waterways and coastal areas.

The Sentinel-2 L2 data are downloaded from COPERNICUS. They were
computed by running sen2cor. The assets contain
12 UINT16 spectral bands representing SR scaled by 10000 (unlike in L1 data,
there is no B10). There are also several more L2-specific bands (see band
list for details). See the
Sentinel-2 User Handbook
for details. In addition, three QA bands are present where one
(QA60) is a bitmask band with cloud mask information. For more
details, see the full explanation of how cloud masks are computed.

EE asset ids for Sentinel-2 L2 assets have the following format:
COPERNICUS/S2_SR/20151128T002653_20151128T102149_T56MNN. Here the
first numeric part represents the sensing date and time, the
second numeric part represents the product generation date and
time, and the final 6-character string is a unique granule identifier
indicating its UTM grid reference (see MGRS).

For more details on Sentinel-2 radiometric resoltuon, see this page.