The call would be same as [SQlite3::createAggregate](https://www.php.net/manual/en/sqlite3.createaggregate) or [PDO::sqliteCreateAggregate](https://www.php.net/manual/en/pdo.sqlitecreateaggregate), parameters are PHP function names, as strings.
So, something like:
$db->sqliteCreateWindow('sumint', 'sumintStep', 'sumintFinal', 'sumintValue', 'sumintInverse')
where those strings are names of window function being defined, and functions user must write in php to implement it.
And, yes, it requires PHP/PDO modifications that are beyond my knowledge.<br>
Thank you for your answers<br>
Best regards<br>
Mar Zama