Thirteen patches posted today add virtual display functionality to the kernel driver. This feature allows other kernel modules and user-space components to work off a fake display engine without even realizing it's a virtual display.
The contents of the virtual display can be accessed through remote desktop tools, etc. The use-case for this virtual display support are for headless GPUs, pre-silicon hardware bring-up testing, GPUs/accelerators with disabled display outputs (such as some workstation cards), and other cases where a virtual display may be desired without sending the rendered screen off to a physical device.
More details via the patch series. Alex Deucher also commented that this virtual display support makes it look like a regular KMS CRTC/encoder/connector and will work fine with all user-space components unchanged -- i.e. desktops, xrandr, and related utilities really don't know they are running on a virtual display.