X11 is a window system. An X client is an application that uses the X protocol (e.g., Firefox, GIMP, LibreOffice) while an X server is an implementation of the X protocol that handles the rendering. Note that an X server and an X client don't have to run on the same machine; if I log into a remote server and execute LibreOffice, LibreOffice is still the X client and my machine's X implementation is still the X server, despite the fact that LibreOffice is running remotely.
XFree86 is a specific X server implementation, though it has been superseded by X.org sometime around 2004 due to a license change from the MIT license to the 4-clause BSD license, which is incompatible with the GPL. X.org is by far the most dominant X server implementation in the free open source software community, but it is not the only implementation; off the top of my head there were proprietary X server implementations for SunOS and NeXT.
> though it has been superseded by X.org sometime around 2004 due to a license change from the MIT license to the 4-clause BSD license,
My understanding is that the scene for the fork had already been set by the time of the relatively late license change. I seem to recall reading at the time that the XFree86 core team was unhappy that a sole contributor was attempting to modernize the system by introducing extensions, without building consensus around them to their satisfaction.
So the license change was meant to prevent forks from merging in further work on XFree86.
Of course the fork was adding functionality everybody wanted. So the fork survived and upstream languished.
Based on my understanding, the license change was "the straw that broke the camel's back." There were already murmurs of a fork due to disagreements among XFree86 developers, but the license change was the final push that led to distributions choosing not to adopt XFree86 4.4, the first version with the new license.
> I seem to recall reading at the time that the XFree86 core team was unhappy that a sole contributor was attempting to modernize the system by introducing extensions, without building consensus around them to their satisfaction.
This is a kind of odd retelling/interpretation of events, considering the “rogue” contributor version is the only one that lived and XFree86 is history.
You may find it odd, but that is what the other, now long forgotten side said at the time, and I'm describing that without taking their side. I noted neutrally as I could that they were "unhappy" and consensus was not built "to their satisfaction", but then that their project soon died because interesting work was going on in the fork.
They envisioned a world in which they needed license changes to block the fork from stealing all their work... And worthwhile contributions from their side did not materialize.
I mean I think the “sole” contributor your are referring to is Keith Packard? Don’t see any reason to not name names here. In any case I guess what I find odd is that while he did a shit ton of work in spearheading a fork, it’s not like it was just him. There were a lot of people, greatly outnumbering the XFree86 steering committee that were unhappy with the direction of the project. It’s not like it was just Keith. That’s what I find odd about your assessment. Obviously there was enough consensus to fork.
You will note that Keith is directly blamed for the fork and undermining XFree86. It sounds like there is also resentment for how XRENDER was done, also driven by Keith, but it would seem with more cooperation within the project. We know that the fork was the victor in history and XFree86 looks unreasonable to most observers but I was merely trying to accurately convey the other side in the dispute, without taking their side.
It does seem like there were a bit of tensions between "Linux on the desktop" types (driven by end user visible features and represented by the fork) and more conservative "old hand at X" types present in the thread, resisting such changes, maybe sometimes for good reasons and sometimes for bad. Though when I google around, it seems Keith and others were active in X before the rise of Linux.
Suffice it to say that Packard was involved in X before XFree86. But the point was that although he was an actual productive contributor he was far from working outside of a consensus. There’s really no sides here. The market could have continued with XFree86, it did not.
While it's true that originally X was network transparent, this hasn't truly been the case for a long time now. All modern applications (including the ones you've listed) render the whole window locally for performance reasons. This does not work over the network. Instead, xorg will transmit a picture of the window, giving you an in many ways worse version of VNC. The only difference is the level of integration with other programs like SSH.
XFree86 is a specific X server implementation, though it has been superseded by X.org sometime around 2004 due to a license change from the MIT license to the 4-clause BSD license, which is incompatible with the GPL. X.org is by far the most dominant X server implementation in the free open source software community, but it is not the only implementation; off the top of my head there were proprietary X server implementations for SunOS and NeXT.