You have been quick. I also thought of this
Paraview supports either OpenGL or EGL as rendering engine. OpenGL accepts either Qt5, Mesa or OSMesa as frontend, while EGL accepts either Mesa or OSMesa. For Windows and macOS only the pair OpenGL/Qt5 is permitted. A ParaView built without Qt5 will have no user interface.
I will consider contributing directly in the future as my familiarity with Paraview grows. For the moment my primary interest is to get it working in parallel: vtkSocketCommunicator errors: "Could not receive tag" and "Endian handshake failed" – with apologies for the shameless promotion of my pains.