ClaudiusH
Pretty much everything you see on NRDLY is built from scratch, including the library and the events. I installed a few community extensions at the very beginning, but some of them have already been replaced by my own modules in the meantime. If I counted correctly, there are currently 29 custom modules running.
As for 2.0, I honestly haven't thought much about it yet. I'm still busy building things on the current version and having fun with it. Once 2.0 is out as a stable release, I'll take my time and look into it properly. I think I'll manage, but with a big version jump you always worry a bit that your own modules will need a lot of changes or stop working. We'll see. Good to know there are tools to help with the upgrade, I'll definitely check them out.
Subarist
Thanks, glad you like it! The reason behind the preview cards is mostly privacy. Here in Germany (and the EU in general) GDPR is a big deal, and if I embedded YouTube directly, visitor data would be sent to Google as soon as the page loads. With the preview cards my server fetches the video info itself, so no user data leaves the server unless someone actually clicks through to the video. For me that was the cleanest solution in terms of data protection.