Hi, Both tables in $subject (in datatype.sgml and xfunc.sgml, respectively) contain similar information (though the xfunc one mentions C structs and header files, and the datatype one does not, but has a description column) and seem similarly out-of-date with respect to the currently supported types ... though not identically out-of-date; they have different numbers of rows, and different types that are missing.
How crazy an idea would it be to have include/catalog/pg_type.dat augmented with description, ctypename, and cheader fields, and let both tables be generated, with their respective columns? Regards, -Chap