They're used to determine the width of the columns in the report. I think this is a flawed approach, and in a future PR would recommend we clean up this logic.

Originally, the app would estimate the column widths and placement based on the data type (from the schema) and add them as hidden fields in the form, and thus would save the widths in the actual data object. The plugin would also make estimates at display time, and let those estimates be over-ridden by what was in the form.

Since it's just display information, I suggest the better way is to refactor the width-estimation logic into a new place, and use it only on display, thus simplifying the form, and reducing the need for these fields.

Feels outside the scope of this PR though?