@juangea , actually I’m afraid that isn’t a very accurate description of the various terms.
Hololens, NReal, TiltFive and Magic Leap are all very clear AR devices and some of these have been around longer than phone based AR.
AR, indeed Augmented Reality, has always been a term to mean that you overlay virtual elements over the real world, you are augmenting the real world. The method by which you do this is not important, whether overlaying on real world camera footage (phone AR and passthrough AR), or by projecting an image in front of the players eyes, it’s all AR.
Phone based AR was mostly introduced as a stepping stone and there is very little focus on this by the industry with only Apple really pushing it further but mostly to get people ready for the Vision Pro, so I think ARKits days are numbered.
I do think this is a mistake, I think phone based AR has many use cases and I wish we had better support for it. But it has been hard finding people with an existing skillset who wish to spend their free time on implementing this and without industry interest it’s hard to find funds to get paid people to do this.
XR was designed as a catchall acronym. OpenXR was named as such to make it clear that it covers all devices, the X basically standing in for any letter and not really meaning anything (though some have adopted it to mean eXtended).
Again Hololens being one of the first to adopt OpenXR (Microsoft was a very early adopter of the standard) as an AR API, sadly Hololens being UWP and DirectX only we never managed to get Godot running on it.
Magic leap adopted OpenXR for their Magic leap 2 headset, again a full AR headset that runs Godot through OpenXR 
NReal is an unknown at this time but rumoured to have an OpenXR API in the works (or possibly released) so hopefully we’ll be able to run Godot on that as well.
TiltFive is the other exception as their feature set isn’t well covered by OpenXR (yet), but we support them through a separate plugin.
The problem OpenXR right now has is that while the core feature set for AR is there, many of the features found in ARKit and ARCore are still missing from the spec. I believe even Microsoft kept some of their features part of their proprietary APIs. There are various vendor extensions being added but AR support in OpenXR needs more maturing. I do think this will ramp up as companies like Magic Leap, Varjo, Meta and Lynx are all investing heavily in making AR happen.
Sadly the term XR also has the problem that it has been appropriated by the eXtinction Rebellion movement, while I won’t cast judgement on that movement, it has resulted that if you search for XR on social media or google, you’re unlikely to find topics that has anything to do with VR or AR.
Finally MR - Mixed Reality, which is probably the most confusing term of all because it means different things to different people.
Microsoft started using it to refer to their Windows Mixed Reality platform because that platform supported both their AR device (the Hololens) and VR devices (Acer, HP, Lenovo, etc. headsets) with the hope that people would adopt their VR devices as a stepping stone to creating AR applications for the Hololens.
At the same time Oculus and a number of other developers of similar solutions adopted MR to mean combining video of the person wearing the headset, with a matching virtual camera view to create a 3rd person view of the game being played which is a much more enjoyable experience for spectators or when capturing footage of someone playing a VR game (see tools like Liv or Mixcast).
Finally indeed, MR was adopted by some as a catch all phrase, possibly because they didn’t like XR as a term.
I can really see why Apple wants to move away from the terminology and is calling it spatial computing now.
