ah, very cool, that’s a fork of my colleague’s Linux-only example from here: https://gitlab.freedesktop.org/monado/demos/openxr-simple-example/ It is very useful in understanding the general concepts of OpenXR and the steps you’d probably go through, even though you would almost certainly not structure your own application as essentially a single function of straight line code.
While I wouldn’t in general look to the conformance tests for guidance in how to use OpenXR or in best practices (since their goal is to test behavior of the runtimes in the common and uncommon corners of the spec, for both valid and invalid behavior), I do know that the CTS tests the three common render setups: one swapchain per eye, one double-wide swapchain using subrects, and a swapchain that is an array, one slice per eye.
Hello-XR is in fact not old, it’s regularly maintained and updated, but it does have a challenge as the most prominent non-engine example code. We chose to demonstrate the general process of how you might write a multi-API, multi-platform app in OpenXR, as well as an app that would very easily run on every OpenXR platform. However it’s definitely not optimized or sophisticated in terms of rendering (much like the namesake “hello world” applications are usually not sophisticated in terms of terminal control and text rendering) as there are better examples for that - plus it tends to be highly graphics-api-specific. Just different objectives to optimize for: a different point in the space of “sample OpenXR apps” than e.g. the “openxr-simple-example” discussed earlier.
It is open-source, btw, so you are welcome to submit changes to add “multi-view” rendering support, for review and possible merging, if it doesn’t distract too much from the underlying OpenXR APIs.
And yes, for better or worse the bulk of reference material out there is relating to the engines: they do represent the bulk of development on OpenXR. That said, we are working to improve our app-developer-focused documentation as well. There is actually a chunk of docs out there but it tends to be scattered across vendor web sites right now. We had a list of references and links at one point but I couldn’t find it last time I looked.