Add ability to disable OS detection in kbd shortcode?

[cscheid]

Discussed in #13487

^{Originally posted by andrewheiss October 1, 2025}

Description

The kbd shortcode is really helpful for formatting keyboard shortcuts across operating systems.

In Javascript-enabled outputs, it uses some fancy logic to replace keys with their macOS equivalents, so that Command becomes ⌘, and so on.

This is great for documents that can adapt to the reader's OS. For teaching with slideshows, though, it's a little trickier because the Javascript OS-detection can't be disabled.

For instance, suppose I have this revealjs slidehow:

---
title: "Cross-platform kbd"
format: revealjs
---

## Rendering

To render:

- macOS: {{< kbd Command-Shift-K >}}
- Windows: {{< kbd Ctrl-Shift-K >}}

If I'm showing the slides in a classroom setting using a computer running macOS, the Windows shortcut displays as ^⇧K

Similarly, if I'm showing the slides from a computer with Windows, the macOS shortcut displays as Command-Shift-K

As far as I can tell, there's no way to use the kbd shortcode to get output like this:

It might be helpful for teaching purposes to have a setting/option for the kbd shortcode to disable to OS detection

[cscheid]

Proposal: {{< kbd Shift-Ctrl-K mode=plain >}}

Semantics: if mode=plain is set, then we expect a single positional argument and render that exactly as is.

[andrewheiss]

I like mode=plain!

I was originally thinking something like {{< kbd mac=Shift-Command-K show=mac >}} so that multiple OSes could be included, like {{< kbd mac=Shift-Command-K win=Shift-Control-K show=mac >}} so that the title would still show all the options, but that gets complex since generally people only want to show one OS when using this plain output