It seems all things Google, or at least a few things, are beginning to see updates and light changes a day earlier than what is typical for the company. Usually, Google sends out updates to a handful of their available apps on Wednesdays, but today is seeing yet another one of their apps receive some changes, the latest being YouTube. Unlike the earlier update mentioned for Docs, Sheets, and Slides, though, the changes to YouTube are a little more minor, and the update is not really an update, but rather a server-side change that YouTube started pushing out to users some months back, and now appears to be rolling out to everyone.
The change is the new card-style layout for the video options inside the YouTube mobile app, which you still access via the overflow menu like you did before. Prior to this change, tapping the overflow menu to reveal the video options would dim the video playback on the screen and overlay the options for you on top of it, showing the options for captions, quality, report, and cardboard if it was a video that supported it. The change today takes these options and moves them to the bottom of the screen in a new card-style popup, and while the options more or less remain the same, there have been a couple of tweaks here too.
The quality option now lists the current quality that the video is being viewed in before you tap it to make a change, and the cardboard option has been updated to "view in cardboard," perhaps to make it more apparent as to what it does. Since this is a server-side thing, it's likely that not everyone will see it immediately, but chances are that the visual tweak to the video options layout should be showing up for everyone by the end of the day. Also in regards to YouTube, Google's latest offer for Chromecast owners nets you a YouTube Red subscription for just $0.99 a month for a three-month period, so if you own a Chromecast or are planning on buying one, now would be a good time to pick it up before the offer expires.