docs: add Typst equation alt text example

docs/output-formats/typst.qmd

@@ -237,6 +237,34 @@ Note that [named Typst colors](https://typst.app/docs/reference/visualize/color/
 
 Typst does not support opacity as a filter, so opacity is simulated using the alpha channel of the color.
 
+## Accessibility
+
+### Equation Alt Text {#equation-alt-text}
+
+Equations in Typst can include alternative text for screen readers.
+Use the `alt` attribute in the equation label:
+
+```markdown
+$$
+E = mc^2
+$$ {#eq-einstein alt="Einstein's mass-energy equivalence equation"}
+```
+
+The `alt` attribute provides a plain-text description of the equation's meaning, which assistive technologies can read aloud.
+Mathematical notation is often inaccessible to screen readers by default, making this particularly valuable.
+
+**Best practices for equation alt text:**
+
+- Describe what the equation represents, not just the symbols.
+- Use plain language that conveys the equation's purpose.
+- Keep descriptions concise but meaningful.
+
+| Equation                | Alt Text                                                 |
+| ----------------------- | -------------------------------------------------------- |
+| `E = mc^2`              | "Einstein's mass-energy equivalence equation"            |
+| `a^2 + b^2 = c^2`       | "Pythagorean theorem relating sides of a right triangle" |
+| `\frac{d}{dx}[f(g(x))]` | "Chain rule for derivatives"                             |
+
 ## Typst File (`.typ`)
 
 The rendering process produces a native Typst file (`.typ)` which is then compiled to PDF using the Typst CLI. This intermediate file is then automatically removed. If you want to preserve the `.typ` file, use the `keep-typ` option. For example:

docs/prerelease/1.9/_highlights.qmd

@@ -4,6 +4,8 @@ Quarto 1.9 includes the following new features:
 
 - [`aria-label` for videos](/docs/authoring/videos.qmd#accessibility-label): Improve accessibility of embedded videos by providing custom descriptive labels for screen readers instead of the default "Video Player" label.
 
+- [Alt text for equations in Typst](/docs/output-formats/typst.qmd#equation-alt-text): Improve accessibility of cross-referenced equations by providing descriptive text for screen readers using the `alt` attribute.
+
 - [`quarto use brand` command](/docs/authoring/brand.qmd#quarto-use-brand): Add or update brand assets from an external source.
 
 - Metadata and brand extensions now work without a `_quarto.yml` project. A temporary default project is created in memory.