The main API that the blog post pointed out is called LauncherOptions.GroupingPreference, which is meant to help your app to tailor its behavior with the new Sets feature in Redstone 5. This was originally announced at Microsoft's Build 2018 developer conference earlier this month.
As usual, this SDK will work alongside of previous SDKs. That means that you can use it in a production environment, as long as the apps that you submit to the Store are targeting a currently supported version of Windows 10.
There are also some known issues to be aware of:
Windows Device Portal
Please note that there is a known issue in this Windows Insider build that prevents the user from enabling Developer Mode through the For developers settings page.
Unfortunately, this means that you will not be able to remotely deploy a UWP application to your PC or use Windows Device Portal on this build. There are no known workarounds at the moment. Please skip this flight if you rely on these features.
Missing Contract File
The contract Windows.System.SystemManagementContract is not included in this release. In order to access the following APIs, please use a previous Windows IoT extension SDK with your project. This bug will be fixed in a future preview build of the SDK.
Another known issue listed is that you won't be able to install this SDK on a non-Insider Preview build of Windows 10; however, another part of the blog post says that it will work. We've reached out for clarification on this.
To download SDK Preview build 17677, you can find it here.