Comment 3 for bug 1318852

Alberto:

This is untrue: "expose an alpha-enabled display framebuffer as we do now"

1. Our servers don't have any alpha channel by default:
    EGLint const config_attr[] = {
        EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
        EGL_RED_SIZE, 8,
        EGL_GREEN_SIZE, 8,
        EGL_BLUE_SIZE, 8,
        EGL_ALPHA_SIZE, 0, <==== No alpha requested

2. Our clients (those that are smart enough) don't have alpha by default either:
   float mir_eglapp_background_opacity = 1.0f; ====> results in non-alpha pixel format selection

But those playing at home should remember that you don't need an alpha channel in either the server or client to do alpha-blending. You still get working shadows and Alt+mousewheel opacity in demo-shell without the need for an alpha channel in the destination buffer.