In some VB6 codes, two-dimensional arrays are referenced as array(1)(1), which is not the same as array(1,1).
VB6 has some limitations on array declarations, and sometimes an array must be declared as an 1D array even though the intent is 2D. In those situations, the tool needs to be told the symbol is a 2D array with a
<FixType identifier="I" type="T" />
The tool actually supports a much richer declarative syntax that VB6, so I guess you can address it with a pre-edit as well, but the
fixtype is a more resilient and more readable technique.