For an xlsx virtual table module I wrote, it also defines an attr function to return metadata. e.g.: ` CREATE VIRTUAL TABLE orders USING xlsxvtab('orders.xlsx','Sheet 1'); SELECT a,b,c,attr(c,'f') AS 'formula',attr(c,6) AS 'format' FROM orders;` The module generates an error if the first argument to attr() does not reference a cell in the virtual table. This is done by having a global attr() function defined at module load and a local scope attr() that overrides it for the table create.