The X Server will [disallow clients with differing endianess](https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1029) in the future. Historically, the X client has sent its own endianess in the connection request (`l` or `B`) with the server then - if required - swapping every request, reply, event from the client's announced endianess to the server-native endianess. This swapping code is hand-written, little tested and very much at the mercy for malicious clients. Quite a number of security issues have been found with that code over the years. Hence the proposed change to simply disallow connections from clients that use different endianess. This is a defaults change. Differing endianess is a niche use-case but still present, see [this fedora-devel thread](https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/PGAHMALQKN6TRNCGFAOE2M4A3GRIL4D7/). To allow clients with different endianess to connect, the proposed X server PR adds an `AllowSwappedClients` xorg.conf option for `Xorg` and a commandline option `+byteswappedclients` for all X server implementations, including Xwayland. In `Xwayland` it becomes kwin's job to pass that flag through to Xwayland - which means there has to be a configurable option somewhere, we definitely don't want this enabled on 99.9% of all users. Note that at the time of writing, the xserver PR is not yet merged and some changes to option naming may happen. *I'm not 100% familiar with the KDE architecture, if kwin isn't what starts Xwayland please move to the right component, thanks*