A new feature in the developer build of the latest Windows update allows users to pair applications for simultaneous use, enhancing multitasking. The update includes a 'frequently snapped apps' section in the Start menu, quicker access to emojis on the Taskbar, improved search functionality, a prompt for adding a recovery email, and tools for web developers. It also addresses various bugs for a smoother user experience. Users can switch between developer and beta access, with the developer build offering early access to features but potentially increased instability.