I’ve seen some confusion about how Mir is supporting Wayland clients on the Phoronix forums . What we are doing is teaching the Mir server library to talk Wayland in addition to its original client-server protocol. That’s analogous to me learning to speak another language (such as Dutch).
This is not anything like XMir or XWayland. Those are both implementations of an X11 server as a client of a Mir or Wayland. (Xmir is a client of a Mir server or and XWayland is a client of a Wayland server.) They both introduce a third process that acts as a “translator” between the client and server.
The Wayland support is directly in the Mir server and doesn’t rely on a translator. Mir’s understanding of Wayland is going to start pretty limited (Like my Dutch). At present it understands enough “conversational Wayland” for a client to render content and for the server to composite it as a window. We need to teach it more “verbs” (e.g. to support for the majority of window management requests) but there is a limited range of things that do work.
Once Mir’s support for Wayland clients is on a par with the support for “native” Mir clients we will likely phase out support for the latter.
We’re still testing things prior to the Mir 1.0 release, and Mir 1.0 will not support “everything Wayland”. If you are curious you can install a preview of the current development version from the “Mir Staging” PPA.