Project Mainline will be part of the Android 10 package when it arrives for Android TV.
With Project mainline on board, Android TV devices will be able to receive important updates quicker than before.
Project mainline won't be much help to existing Android TV devices.
Android 10 for Android TV is coming soon
Over the last few days there has been an uptick in news surrounding Android 10 for Android TV. This is due to information that has leaked from the recent IBC 2019 event. While not confirmed by Google, Android 10's expected Android TV arrival is taking place before the end of 2019.
Very recently the news came through that Android TV device makers no longer need to provide three years of platform updates. Instead, a policy change now means they only need to provide two years.
Although that's not great news from the user perspective, irrespective of how long a device maker opts to support an Android TV device, Project Mainline will likely guarantee important updates for longer.
What is Project Mainline
Google announced Project Mainline earlier in the year as a means to improve Android updates in general.
Project Mainline allows Google to directly update certain components from the Google Play Store. In other words, Google can bypass the device maker when doing this and that's what makes the change so important.
With Project Mainline in effect, important updates will no longer need to go through the Android TV device maker first. Or for that matter, require the device maker to still be supporting the device at the update level. Instead, these components (think security, privacy, performance), will be updated similar to how apps are currently updated.
Not so good news for existing Android TV device owners
Android Headlines has been informed Project Mainline will be included with Android 10 when it rolls out to Android TV devices.
Considering Google announced Project Mainline as an Android 10 feature, many might assume that's enough of a confirmation. While that might be true in general, nothing should ever be assumed with Google and Android.
For example, current Android TV device owners might assume when their device is updated to Android 10 it will also gain Project Mainline support. After all, it's an Android 10 feature. However, that's not the case. If anything, current Android TV device owners should most definitely expect the opposite.
When Google announced Project Mainline it confirmed this as a feature only available to devices running Android 10 out of the box. There are core changes needed for the handover of responsibility from the device maker to Android. Therefore, those changes presumably need to be included in the device's software at creation level, rather than updated over the air.
The good news is Project Mainline is a mandatory feature. Due to this, Google will be in charge of important updates for all Android TV devices that launch running on Android 10 and beyond.
For reference, Project Mainline updates are listed as "Google Play System Updates" when they arrive.