Why isn't Xwayland just a Wayland client?

[Joseph Burt]

To be clear, my first look at how the X11 channel is used in practice
hasn't yet turned up the justification for its existence. The logic
usually seems to be "if X client, send event over X11, else Wayland,"
which is redundant. There must be something big, since tacking on a
X11 channel is a big protocol extension, but I haven't found any
discussion of that design decision. Can anyone point me in the right
direction?

Thanks,
Joseph

On Tue, Sep 5, 2017 at 7:51 PM, Joseph Burt <caseorum at gmail.com> wrote:
> Most Wayland compositors, Weston and WLC-based ones included, carry
> around a bit of XWM code, essentially a protocol extension, to deal
> with Xwayland. Why? What is lacking in Xwayland?
>
> Thanks,
> Joseph