Add own parameters into JetEngine Listing query args

gistfile1.txt

<?php

add_filter( 'jet-engine/listing/grid/posts-query-args', function( $args, $widget, $settings ) {

	if ( 'custom-query' === $settings['_css_classes'] ) {

		$args['meta_query'][] = array(
			'relation' => 'OR',
			0 => array(
				'key' => 'submission-date',
				'value' => strtotime( 'Today' ),
				'compare' => '>=',
				'type' => 'NUMERIC'
			),
			1 => array(
				'key' => 'submission-date',
				'value' => '',
				'compare' => '=',
			),
		);

	}

	return $args;
}, 10, 3 );