Impossibility to fence a code chunk with the chunk option `include: false`?

[elenlefoll]

I have:

• searched the issue tracker for similar issues
• installed the latest version of Quarto CLI
• formatted my issue following the Bug Reports guide

Bug description

For a textbook I would like to explain to students that they can use the code chunk option include: false to run a chunk, but not display it or its output in their rendered document. I would like to be able to display this demo chunk in the rendered version of my textbook and, for this, I used the echo: fenced option. However, the problem is that the chunk is not displaying in the rendered doc (see reprex below).

Steps to reproduce

---
title: "Fencing a code chunk with option include: false"
date: last-modified
author: Elen Le Foll
---

For a textbook I would like to explain to students that they can use the code chunk option `include: false` to run a chunk, but not display it or its output in the rendered document. I would like to be able to display this demo chunk and for this I used the `echo: fenced` option. However, the problem is that the chunk is not displayed in the rendered doc.

```{r}

#| echo: fenced
#| label: demo-chunk
#| include: false

demoplot <- plot(1:10)

```

Actual behavior

The code chunk is not displayed in the rendered doc.

reprex.html

Expected behavior

The code chunk should be rendered including with the opening and closing backticks.

Your environment

• IDE: RStudio Version 2026.01.1+403 (2026.01.1+403)
• MacOS Sequoia 15.4.1 (24E263)

Quarto check output

Quarto 1.9.30
[✓] Checking environment information...
      Quarto cache location: /Users/lefoll/Library/Caches/quarto
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.8.3: OK
      Dart Sass version 1.87.0: OK
      Deno version 2.4.5: OK
      Typst version 0.14.2: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.9.30
      Path: /Applications/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: v2025.11
      Chromium: (not installed)
      Chrome Headless Shell: (not installed)
      VeraPDF: (not installed)

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /Users/lefoll/Library/TinyTeX/bin/universal-darwin
      Version: 2025

[✓] Checking Chrome Headless....................OK
      Using: Chrome found on system
      Path: /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
      Source: MacOS known location

[✓] Checking basic markdown render....OK

[✓] Checking R installation...........OK
      Version: 4.5.2
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library
      knitr: 1.51
      rmarkdown: 2.30

[✓] Checking Knitr engine render......OK

[✓] Checking Python 3 installation....OK
      Version: 3.12.8 (Conda)
      Path: /Users/lefoll/miniconda3/bin/python
      Jupyter: (None)

      Jupyter is not available in this Python installation.
      Install with conda install jupyter

[✓] Checking Julia installation...

[mcanouil]

That's not a bug.
The result is exactly as expected:

Catch all for preventing any output (code or results) from being included in output.

Use escaping for these cases:

```{{r}}
#| label: demo-chunk
#| include: false

demoplot <- plot(1:10)
```