Up until recently Windows Mixed Reality headsets only worked when you were also connected to a monitor, which was rather awkward when using backpack VR setups.
Now in the latest Insider Build for Windows 10 Microsoft has removed this restriction. With Build 17686 you can simply run with only the backpack and a headset. You still need a monitor to set up for the first time, of course, but afterwards, you can have auto-login configured and do without the display.
Other improvements are that developers can now use the Camera Capture UI API to take screenshots of the VR world and paste these directly into apps and Microsoft also improved the ability to stop video capture via the Start menu.
The tweaks should come in handy where VR is used in a professional setting such as industrial design. Insiders can find the improvements by Checking for Updates in Settings.