Microsoft has been releasing new builds of the Windows 10 SDK and Windows Server in line with Windows 10 Dev channel builds for some time now, and this week is no exception. Build 20170 of the Windows Server and Windows 10 SDK previews are now available.
Last week, Microsoft briefly published build 20165 of both Windows Server and the Windows 10 development kits, but it was pulled sometime after that. There also wasn't a new Windows 10 build in the Dev channel last week, so the other builds might have been published by accident.
As we've seen with pretty much all the recent preview releases, Microsoft isn't bothering to post changelogs for any of the builds outside of the regular Windows 10 ones. Some of the recent builds on that side of the Insider program have had fairly significant changes, so there might be something interesting in these builds too, but Microsoft isn't saying.
If you want to find out for yourself, you can download the latest Windows Server Insider Preview builds from the respective webpage. Likewise, you can download the latest Windows 10 SDK Preview here, grab the ADK here, and the WDK here.