Columns the screener can show, filter or sort

Every column the screener knows: its key (use it in fields), label, group, kind, and whether it is fixed (already in every result). A field the screener can order by carries sort, the value to pass as the sort parameter (the sort keys predate the catalogue, so total_assets sorts with sort=assets). A field with a range filter carries min_param and max_param, the query parameters that bound it (total_assets is filtered with min_assets / max_assets). Both are absent where they do not apply. max_fields is the most keys fields accepts.