修改extend.php
use Flarum\Extend;
use Flarum\Frontend\Document;
return [
(new Extend\Frontend('forum'))
->content(function (Document $document) {
$document->head[] = 'HEAD HTML HERE';
})
]参考来源：https://discuss.flarum.org/d/7365-how-to-add-meta-tags-to-head/9
