Here is a list of all documented variables with links to the struct/union documentation for each field:

ambiguous_width : utf8proc_property_struct
bidi_class : utf8proc_property_struct
boundclass : utf8proc_property_struct
category : utf8proc_property_struct
charwidth : utf8proc_property_struct
comb_index : utf8proc_property_struct
decomp_type : utf8proc_property_struct
ignorable : utf8proc_property_struct