init.php

<?php

class ff_nonprintables extends Plugin {
    private $host;
    function about(){
        return array(0.1, "nonprintables", "peppec", false);
        // inspired by https://github.com/fastcat/tt-rss-ff-xmllint
    }

    function api_version(){
        return 2;
    }

    function init($host){
        $this->host = $host;
        $host->add_hook($host::HOOK_FEED_FETCHED, $this);
    }

    function hook_feed_fetched($input){
        return preg_replace('/[\x00-\x08\x0e-\x1f]/', '', $input);
    }
}