FILR disallow additional file types for the upload

functions.php

<?php 
add_filter('filr_disallowed_file_extensions', function( $extensions ) {
	// Extensions contains an array by default which looks like this:  array( 'htaccess', 'php', 'php3', 'php4', 'php5', 'phtml' ).
	// Lets exclude HTML files here.
	$extensions[] = 'html';

	return $extensions;
});