Microsoft has released a new cumulative update for Windows 10 build 20262, which was recently released to Insiders in the Dev channel. It doesn't include new features. Microsoft's intention is to test their servicing pipeline.
The update will become available automatically if your device is configured to receive updates from the Dev channel.
Windows 10 build 20262 is a software from the FE_RELEASE branch. It was released to the Dev channel, and comes without new features. Instead it includes some fixes, and also has a number of known issues.
You can learn more what's new in Build 20262 in the following post:
The Dev Channel, formerly known as the Fast Ring, reflects the latest changes made to the Windows code base. It is a work-in-progress, so the changes you see in Dev Channel releases may not appear in the upcoming feature update. So we can expect to see some features which will never appear in stable Windows 10 versions on Desktop.
Also, it is possible that Microsoft will bring some Windows 10X features to Windows 10 on Desktop. Microsoft is about to add some of Windows 10X's features to get the best of two Windows branches. The company may also replace some of the Desktop feature updates with Windows 10X releases.
If you have configured your device to receive updates from the Dev Channel/Fast Ring ring, open Settings - > Update & recovery and click on the Check for Updates button on the right. This will install the latest available Insider Preview of Windows 10.