where to make pull request for customizing page subtitle

Hi I’d like to suggest adding a filter so I can customize the archive page’s subtitle. Do you guys have a github repository for this theme? Or how can I submit the change?

I just changed templates/page-header.php to start with

<?php
	 if(!pinnacle_hide_pagetitle()) { ?>
<?php } else {
	global $post, $pinnacle;
	if(is_page()) {
		$bsub = get_post_meta( $post->ID, '_kad_subtitle', true );
	} else if(is_category()) {
		$bsub = strip_tags( category_description() );
	} else if(is_tag()) {
		$bsub = strip_tags( tag_description() );
	} else {
		$bsub = '';
	}
	$bsub = apply_filters( 'kadence_page_subtitle', $bsub, $post, $pinnacle );
	 ?>

Notice the new else statement, and the added filter.