I deliberately put the paragraph about rendering first, because you can't talk about HDR output before explaining what HDR actually is.
Topic on Glossary talk:High dynamic range (HDR)
> "High Dynamic Range output or High Dynamic Range is a technology that first and foremost enables a screen to display an image at a much greater range of contrast. In practice this usually goes hand in hand with an increased color bit depth from standard 8-bits per color to 10-bits per color or more. In any case, both the software, graphics card (incl. driver), connection and display need to support this technology in order to actually be able to put a HDR image onto a HDR display."
The above is more than enough to explain the basics. People don't have to read the "HDR rendering" section to understand the "HDR output on a HDR display" section, which is what most people care about.
We should preferably list the two sections in order of importance and relevance, and the HDR rendering section is not as relevant or important today.
This ties into the "High dynamic range display (HDR)" option in the video settings template as well, which links to this glossary page. Listing "HDR rendering" first can incorrectly make new editors or readers believe that any and all games that supports HDR rendering should be treated as true, e.g. even older games like Half-Life 2 and the like should be set to true.
Nobody cares about the technicalities behind the feature. Everyone cares about what's relevant to them >right now< and what's required of them, and that's covered in the "HDR output on a HDR display" section.
Further on, "HDR rendering" only discusses HDR from a game and rendering perspective. It is not relevant to e.g. video content that have been recorded in HDR, which is also of interest today and should be at least partially accounted for.
All in all, we don't gain anything by listing "HDR rendering" first, and only introduces potential for misunderstandings.
You say that as if the current content is set in stone and those 2 sections are all there'll ever be. And again, you explain a topic step by step. In this case: by explaining what "HDR" (which is what the topic is, not "HDR output") actually is, then you can talk about how to make use it. Otherwise you might as well not explain HDR at all.
> "You say that as if the current content is set in stone and those 2 sections are all there'll ever be."
I am not. But the other order of those two sections better bring the >current< focus of the glossary page across. It is, as I mentioned, important to properly educate readers and authors that e.g. Half-Life 2 isn't relevant in terms of modern focus of the "HDR" term in relation to gaming.
> "And again, you explain a topic step by step. In this case: by explaining what "HDR" (which is what the topic is, not "HDR output") actually is, then you can talk about how to make use it. Otherwise you might as well not explain HDR at all. "
"HDR rendering" describes what >HDR rendering< is, not what >HDR< as a whole is about. And again, it is not necessary to understand the specifics of HDR rendering to understand the main purpose of HDR output, which is as I've mentioned the primary focus of the glossary page right now.
It's why the HDR rendering section is better listed further down the article, as you start by a short summary to get the key points of the glossary page across (HDR output in relation to PCs), and then expand upon it with details further down (how HDR rendering works internally).
It is also why e.g. Wikipedia's own HDR article looks as it does, with more in-depth information scattered in relevant sub-articles, one of which is about HDR rendering.
The summary is already at the very top: the "key points". Then you explain what the term "HDR" actually means, then how "HDR output" is a new thing. If you don't agree with that, then I have nothing else to say. That's basic article structuring. This is not a blog where the most recent changes are at the top.