YouTube is probably the most popular Google app, outside of Gmail. Many users spend hours a day using the app to watch video and such, especially with more and more people cutting the cord to their TV. But seeking in the app has been a bit cumbersome for some users. While you can definitely scrub and go forward or back in the video, it's not a great experience when you are watching a longer video, as you can quickly jump a few minutes, instead of just a few seconds.
It now appears that YouTube is going to be adding a double tap to seek feature. In the current version of the app, that is beginning to roll out right now, YouTube is adding the ability to double tap and go forward or back up to 10 seconds at a time. Making it a whole lot easier to jump back a few seconds and see something you may have missed. Currently, the feature is not working in YouTube, by default. And you do need to do a bit of trickery to get it to work. Basically, what you need to do is go into the settings, and find the YouTube app in the app section. Then you'll need to tap on Storage, and then "Clear data". Once you've cleared the data, just go back into the app like normal, and you'll be able to double tap on either the left or right side and go back or forward by 10 seconds.
Overall, it's a pretty simple UI change, but it appears that the YouTube team doesn't think it is quite ready for primetime, hence the reason why it's not working by default. But this is a feature that you may see in the YouTube app in the next few updates. Other than this, there is very little new in this update. There are the usual bug fixes and performance improvements, but that is about it. You can sideload the update, bringing you to version 11.47, by downloading the APK from the link below. Remember to tick "Unknown Sources" in the security section of the settings.