For example, if a prepared statement is created using the SQL text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 and parameter :xyz is unbound, then sqlite3_sql() will return the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() will return "SELECT 2345,NULL".
alternatively, a monitor for sqlite would also be fine to view the queries launched by the program, but I don't know any