Microsoft is redesigning the "Settings and more" menu in Edge by organizing menu options with icons and keyboard shortcuts. Users can see top sites in the Jump List on the Windows taskbar or Start Menu. And users can more easily organize groups of tabs that they've set aside with this build.
Under the UI covers, Microsoft is adding support for IPv6 to KDNET. The company also is making a change in how memory used by suspended Universal Windows Platform apps/processes appear in Task Manager, according to the blog post about 17677.
Microsoft also is redoing the mobile broadband (LTE) networking stack via the NetAdapter framework by adding a new network driver model. The post says more details will be coming soon about this. Microsoft added a "new and improved" Mobile Broadband USB classdriver based on the NetAdapter framework to Redstone 5 with Build 17655. Starting with this build, this driver becomes the default driver.
Microsoft made a number of other fixes and updates to this build in Edge, Narrator and with the Command Prompt. There are several known issues with this build, including one specifically for those participating in the Windows Insider Program for Business testers: There's an issue blocking those using Azure Active Directory from receiving new flights, which Microsoft hopes to fix ASAP in an upcoming build, according to the release notes.
Redstone 5 is expected to begin rolling out to mainstream users around October 2018.