Much like other Google products and services, YouTube has often experimented with features before choosing whether or not to roll them out to the masses. The company already had a portal for accessing unfinished features, at youtube.com/new, but now the hub will only be accessible to YouTube Premium subscribers.
The page for experimental features now says, "for a limited time, Premium members can try out new features that we’re working on. Share your feedback to help us build a better YouTube." There are currently three features available for testing — voice search on Chrome, topic filters for languages, and additional playback options for the iOS app.
It is a bit strange that experimental functionality is now locked behind a Premium subscription, but there's nothing especially compelling that non-paying people will miss out on. YouTube also regularly tests new features in limited server-side trials, which often affect both regular and Premium users. If a new feature does appear in the testing page that ends up being popular, the increased attention will likely increase the chances that it will roll out to everyone.
- Android Central