> Zed probably has implicit support requirements which wouldn't apply to e.g. the last first-person shooter.

This is incongruous given Zed uses modern frameworks (which is why they moved to D3D11 from Vulkan in the first place).

If Zed really wanted to target 'old Windows' then they might have used Win32 and GDI+, not D3D11. In fact they could've stuck to D2D (which was released with Windows 7 and back-ported to Vista), and not used their own rendering at all, since D2D is already a GPU-accelerated text-rendering API, and then used Win32 windowing primitives for everything else.