Snippet to exclude Gravity Forms hidden field from "all_fields" merge tag

gf-exclude-hidden-fields.php

<?php

add_filter( 'gform_merge_tag_filter', 'filter_all_fields', 10, 6 );
function filter_all_fields( $value, $merge_tag, $modifier, $field, $raw_value, $format ) {
	if ( $merge_tag == 'all_fields' && $field->type == 'hidden' && $field->id == '10' ) { // Replace 10 with your hidden field id
			return false;
	} else {
			return $value;
	}
}

?>