FILTER() finds all rows in a table, named by table-name, that match a criteria, expressed by select-row?.
table-name must be a literal Text value; it cannot be an expression.
select-row? is an expression that returns a Yes/No value (TRUE or FALSE) indicating whether a given row should be included in the results.
select-row? is evaluated once for each row in the table named by table-name.
A Ref list: the key of each row selected by select-row? in the table named by table-name.
The results list is in an arbitrary order, subject to the internal needs of the function; any apparent ordering should be considered coincidental.