[jjcm]

I'm excited for this simply because it means you can have a fully client side in browser youtube downloader. With things like youtube-dl, you need ffmpeg to combine the higher bitrate streams if you're downloading anything 1080p and above. Most downloaders offload to a server to handle this, but it always bugged me when I had to do that.

[TD-Linux]

That's not actually what it means at all. youtube-dl doesn't reencode, it just remuxes the audio and video streams back together. You could do this in JS already.