Modify what tag attributes SearchWP considers valuable when indexing

gistfile1.php

<?php

function my_searchwp_indexer_tag_attributes( $tags ) {
	
	// do not index img tags at all
	if ( isset( $tags['img'] ) ) {
		unset( $tags['img'] );
	}
	
	// index our custom Reference data attribute on <article>s
	$tags['article'] = array( 'data-reference' );
	
	return $tags;
}

add_filter( 'searchwp_indexer_tag_attributes', 'my_searchwp_indexer_tag_attributes' );