what is 'freeform subtype' section is??

my asrock board coantian setup section and
in this section there are (pe32+ image, freeform subtype’)
exist and freeform subtype section include unicode text

it seem that unicode text in ‘freeform subtype section’ referenced by some place in pe32 image section but i do not know exact place…

how can i find the the code referencing unicode text in ‘freeform subtype section’??