GravityView - Change the default <select> option value

gravityview-change-select-default.php

<?php

/**
 * Modify the text for the default option in a select (multi or single dropdown)
 *
 * @param string $default_option Default: `&mdash;` (—)
 * @param string $field_type Field type: "select" or "multiselect"
 * 
 * @return string
 */
add_filter( 'gravityview/extension/search/select_default', function( $default, $select_type = 'select' ) {

	if( 'select' === $select_type ) {
		return '-- Select --';
	}
	
	return '-- Select One or More --';
}, 10, 2 );