Windows 10 build 17728.1000 is interim release as Redmond works to debug the Redstone 5 version of Windows 10 which will be called version 1 809 when its released.
This version is designed for a new round of debugging which will run until August 5, 2018.
The features are frozen and the effort is mostly for fixing as many problems as possible.
The Narrator has been improved and now it supports Braille for those who are unable to see clearly. With an older population vision loss has motivated Redmond to add more accessibility to Windows.
Microsoft also has been working on the phone app to make it work better than the last version. Things like sending a link from the phone to the laptop/desktop and more are being supported.
We did note that this build was slower than most to install. We suspect that this is due to the rollback recovery needing more time to backup files. We are using SSD which are faster to install an operating system on.