Recently, YouTube went down for one hour straight. However, after the site went up, an unexpected launch took place: YouTube Beta app. Most of panicked, abusing our ISPs and what not. Yes, that actually happened. But, under the cover of the outage, Google launched the YouTube Beta version.
But, you know Google. Even though they make beta signup public, they do changes at their end, making the front-end user know about nothing. However, With the Chrome Beta, it might be possible to see changes at our end as well.
Right Now, The Beta signup is currently open. You can go forward and sign up for the same
Source: Android Authority