The true color product maps MODIS band values B01, B04, and B03 which roughly correspond to red, green, and blue part of the spectrum, respectively, to R, G, and B components. The result is a true color product, that is a good representation of the Earth as humans would see it naturally.
True color composite for MODIS: B01, B04, B03
MODIS true color image of Europe. Acquired on 2021-08-02, processed by Sentinel Hub.