Overwriting Data for CADRG raster using ArcMap

I read this ArcGIS Resources about Overwriting Data for CADRG raster and try to understand, http://resources.arcgis.com/en/help/main/10.2/index.html#//000n0000005q000000#:~:text=When%20you%20add%20military%20products%20such%20as%20CADRG%2FECRG%2C,it%20has%20been%20added%20to%20a%20mosaic%20dataset.
It is mentioned that:

For CADRG/ECRG and CIB data, the NITF file date/time value is used for
the comparison

Could you confirm which field of data NITF file date/time refers to when it is comparing which data is newer?

Is it ImageDateTime or FileDateTime or something else?