>>12355
yes
>>12356
it's how you specify a list of formats in order of preference. ytdl will then pick the first one that's available from that list

271 looks the best from what I can tell, but it's only available on newer videos.
for the 1080x608 resolution mp4 seems to look better than webm most of the time. 299 is for 60fps
a few videos are only available in 406x720 for some reason, so I'm using 136 as a fallback.

I'm going to add the best available mp4 version as an alternative to the 720p webms in case anyone needs an mp4 for editing