Author of Piped (and also a member of TeamNewPipe and LibreTube) here.
I haven’t seen any changes from YouTube recently, the ways we fetch age restricted content still seem to work for most videos. However, this method may not work for all videos as YouTube has different levels of age restrictions afaict. I’ve seen very few videos fall under that category personally.
If anything were to change in the future, I may consider implementing something similar to what this extension does (or use their API) in Piped.
Hey, thanks for the message! I’ve fixed the issue already, which was caused by a regression in one of my changes. To prevent this from happening in the future, I’ve added unit tests for the same. Sorry for the inconvenience caused!