friendica/mod/manifest.php

<?php
    use Friendica\Core\Config;

    function manifest_content(App $a) {

		$tpl = get_markup_template('manifest.tpl');

		header('Content-type: application/manifest+json');

		$touch_icon = Config::get('system', 'touch_icon', 'images/friendica-128.png');
		if ($touch_icon == '') {
			$touch_icon = 'images/friendica-128.png';
		}

		$o = replace_macros($tpl, array(
			'$baseurl' => App::get_baseurl(),
			'$touch_icon' => $touch_icon,
			'$title' => Config::get('config', 'sitename', 'Friendica'),
		));

		echo $o;

		killme();

	}
?>