EDIT: indeed, it was introduced in 2023: https://blog.arxiv.org/2023/12/21/accessibility-update-arxiv...
> View any arXiv article URL [in HTML] by changing the X to a 5
The line
> Sources upto the end of November 2025.
sounds to me like this is indeed intended for older articles.
I’ve actually dug into this in the past and it was never lack of technical ability that prevented them from even adding just proper superscript/subscript support before, but rather their opinion that this didn’t belong in the symbolic layer. But since emoji abuse/rely on ZWJ and modifiers left and right to display in one of a myriad of variations, there’s really no good reason not to allow the same, because 2 and the squares symbol are not semantically the same (so it’s not a design choice).
An interesting (complete) tangent is that Gemini 3 Pro is the only model I’ve tested (I do a lot of math-related stuff with LLMs) that absolutely will not under any circumstances respect (system/user) prompt requests to avoid inline math mode (aka LATeX) in the output, regardless of whether I asked for a blanket ban on TeX/MathJax/etc or when I insisted that it use extended unicode codes points to substitute all math formula rendering (I primarily use LLMs via the TUI where I don’t have MathJax support, and as familiar as I once was with raw TeX mathematical notations and symbols, it’s still quite easy to confuse unrendered raw output by missing something if you’re not careful). I shared my experiment and results here – Gemini 3 Pro would insist on even rendering single letter constants or variables as $k$ instead of just k (or k in markdown italics, etc) no matter how hard I asked it not to (which makes me think it may have been overfit against raw LATeX papers, and is also an interesting argument in favor of the “VL LLMs are the more natural construct”): https://x.com/NeoSmart/status/1995582721327071367?s=20
> 1. TeX has many advantages that make it ideal as a format for the archives: It is plain text, it is compact, it is freely available for all platforms, it produces extremely high-quality output, and it retains contextual information.
> 2. It is thus more likely to be a good source from which to generate newer formats, e.g., HTML, MathML, various ePub formats, etc. [...]
Not that I disagree with the effort and it surely is a unique challenge to, at scale, convert the Turing complete macro language TeX to something other than PDF. And, at the same time, the task would be monumentally more difficult if only the generated PDFs were available. So both are right at the same time.
As a very brief update - we are pending a larger update.
You will spot many (many) issues with our current coverage and fidelity of the paper rendering. When they jump at you, please report them to us. All reports from the last 2 years have landed on github. We have made a bit of progress since, but there are (a lot of) more low-hanging fruit to pick.
Project issues:
https://github.com/arXiv/html_feedback/issues/
The main bottleneck at the moment is developer time. And the main vehicle for improvements on the LaTeX side of things continues to be LaTeXML. Happy to field any questions.
There used to be another showcase, called arxiv-vanity. They captured what happened pretty well with their farewell post on their homepage:
HTML was explicitly designed to semantically represent scientific documents. [1]
”HTML documents represent a media-independent description of interactive content. HTML documents might be rendered to a screen, or through a speech synthesizer, or on a braille display. To influence exactly how such rendering takes place, authors can use a styling language such as CSS.” [2]
1: https://html.spec.whatwg.org/multipage/introduction.html#bac...
2: https://html.spec.whatwg.org/multipage/introduction.html#:~:...