About reflectance of sentinel-2 image

About the reflectance displayed when opening a band image with sentinel-2 with snap.

The value is different when opening the jp2 image saved in the zip file using python.

What kind of calculation is done when opening with snap?

please tell me.

Here you will probably find all the answers you need:

Thank you for your reply.

I am very happy to have the information.

I will refer to it.