See the [markup reference guide](https://docs.github.com/en/contributing/syntax-and-versioning-for-github-docs/using-markdown-and-liquid-in-github-docs) for more information about supported Markdown features.
- Type: `Object`. Allowable keys map to product names and can be found in the `versions` object in [`lib/frontmatter.js`](/src/frame/lib/frontmatter.js).
You can also version a page for a range of releases. This would version the page for GitHub.com, and GitHub Enterprise Server versions 2.22 and 3.0 only:
The list of popular links are the links displayed on the landing page under the title "Popular." Alternately, you can customize the title "Popular" by setting the `featuredLinks.popularHeading` property to a new string.
- Purpose: Indicates whether an article should show a mini table of contents (TOC) above the rest of the content. See [Autogenerated mini TOCs](#autogenerated-mini-tocs) for more info.
- Purpose: Indicates whether a page is allowed to have a title that differs from its filename. Pages with this frontmatter set to `true` will not be flagged in tests or updated by `src/content-render/scripts/reconcile-filenames-with-ids.js`. Use this value if a file's `title` frontmatter includes Liquid or punctuation that cannot be part of the filename. For example, the article "[About Enterprise Managed Users](https://docs.github.com/en/enterprise-cloud@latest/admin/identity-and-access-management/using-enterprise-managed-users-for-iam/about-enterprise-managed-users)" uses a Liquid reusable in its title, `'About {% data variables.product.prodname_emus %}'`, which cannot be in the filename, `about-enterprise-managed-users.md`, so the `allowTitleToDifferFromFilename` frontmatter is set to `true`.
- Purpose: Render a list of items pulled from [GitHub Changelog](https://github.blog/changelog/) on product landing pages (ex: `components/landing`). The one exception is Education, which pulls from https://github.blog/category/community/education.
-`label` -- must be present and corresponds to the labels used in the [GitHub Changelog](https://github.blog/changelog/)
-`prefix` -- optional string that starts each changelog title that should be omitted in the docs feed. For example, with the prefix `GitHub Actions: ` specified, changelog titles like `GitHub Actions: Some Title Here` will render as `Some Title Here` in the docs feed).
- Purpose: Override the initial platform selection for a page. If this frontmatter is omitted, then the platform-specific content matching the reader's operating system is shown by default. This behavior can be changed for individual pages, for which a manual selection is more reasonable. For example, most GitHub Actions runners use Linux and their operating system is independent of the reader's operating system.
- Type: `String`, one of: `mac`, `windows`, `linux`.
- Purpose: Override the initial tool selection for a page, where the tool refers to the application the reader is using to work with GitHub (such as GitHub.com's web UI, the GitHub CLI, or GitHub Desktop) or the GitHub APIs. For more information about the tool selector, see [Markup reference for GitHub Docs](../contributing/content-markup-reference.md#tool-tags). If this frontmatter is omitted, then the tool-specific content matching the GitHub web UI is shown by default. If a user has indicated a tool preference (by clicking on a tool tab), then the user's preference will be applied instead of the default value.
**Note: the featured track is set by a specific property in the learning tracks YAML. See that [README](../data/learning-tracks/README.md) for details.*
- Purpose: Indicate the topics covered by the article. Refer to the content models for more details about adding topics. A full list of existing topics is located in the [allowed topics file](/data/allowed-topics.js). If topics in article frontmatter and the allow-topics list become out of sync, the [topics CI test](/src/search/tests/topics.js) will fail.
- Optional: Topics are preferred for each article, but, there may be cases where existing articles don't yet have topics, or adding a topic to a new article may not add value.
- **For GitHub staff only**: Set an effective date for Terms of Service articles so that engineering teams can automatically re-prompt users to confirm the terms
- Type: `string` YEAR-MONTH-DAY e.g. 2021-10-04 is October 4th, 2021
If you see two single quotes in a row (`''`) in YML frontmatter where you might expect to see one (`'`), this is the YML-preferred way to escape a single quote. From [the YAML spec](https://yaml.org/spec/history/2001-12-10.html):
Every article displays a mini table of contents (TOC), which is an autogenerated "In this article" section that includes links to all `H2`s in the article. Only `H2` headers are included in the mini TOCs. If an article uses `H3` or `H4` headers to divide information in a way that only certain sections are relevant to a particular task, you can help people navigate to the content most relevant to them by using a [sectional TOC](../contributing/content-style-guide.md#sectional-tocs).
- Determines in which versions the page is available. See "[Versioning documentation](https://docs.github.com/en/contributing/writing-for-github-docs/versioning-documentation)" for more info.
- Conditionally render content depending on the current version being viewed. See "[Versioning documentation](https://docs.github.com/en/contributing/writing-for-github-docs/versioning-documentation#versioning-with-liquid-conditional-operators)" for more info. Note Liquid conditionals can also appear in `data` and `include` files.
**Note**: As of early 2021, the `free-pro-team@latest` version is not included URLs. A helper function called `src/versions/lib/remove-fpt-from-path.js` removes the version from URLs.
When adding a new article, the filename is a [kebab-cased](https://en.wikipedia.org/wiki/Letter_case#Kebab_case) version of the article's [`title`](#title) frontmatter. For example, the article "[About GitHub CLI](https://docs.github.com/en/github-cli/github-cli/about-github-cli)" has a `title` frontmatter of `About GitHub CLI` and a filename of `about-github-cli.md`.
For a title that contains punctuation (such as "GitHub's Billing Plans"), you can omit the punctuation in the filename (`githubs-billing-plans.md`). For a title that uses a Liquid variable (such as `About {% data variables.product.prodname_emus %}`), you can use the words that the Liquid renders as in the filename (`about-enterprise-managed-users.md`). A test will flag any discrepancies between title and filename. To override the requirement that titles and filenames match for a given article, you can add [`allowTitleToDifferFromFilename`](#allowtitletodifferfromfilename) in the frontmatter.
When using Liquid conditionals in lists or tables, you can use [whitespace control](https://shopify.github.io/liquid/basics/whitespace/) characters to prevent the addition of newlines and other whitespace that would break the list or table rendering.
For example, to version a table row, instead of adding liquid versioning for the row starting at the end of the previous row, like this:
```
Column A | Column B | Column C
---------|----------|---------
This row is for all versions | B1 | C1{% ifversion ghes %}
This row is for GHES only | B2 | C2{% endif %}
This row is for all versions | B3 | C3
```
You can include the liquid versioning on its own line and use whitespace control to strip the newline to the left of the liquid tag. This makes reading the source much easier, without breaking the rendering of the table:
Links to docs in the `docs-internal` repository must start with a product ID (like `/actions` or `/admin`) and contain the entire filepath, but not the file extension. For example, `/actions/creating-actions/about-custom-actions`.
Image paths must start with `/assets` and contain the entire filepath including the file extension. For example, `/assets/images/help/settings/settings-account-delete.png`.
The links to Markdown pages undergo some transformations on the server side to match the current page's language and version. The handling for these transformations lives in [`src/content-render/unified/rewrite-local-links.js`](/src/content-render/unified/rewrite-local-links.js).
If you create an internal link, you can use the AUTOTITLE keyword to generate an article's title in the rendered link. See the [markup reference](https://docs.github.com/en/contributing/syntax-and-versioning-for-github-docs/using-markdown-and-liquid-in-github-docs#internal-links-with-autotitle) for details.
### Linking to the current article in a different version of the docs
Sometimes you may want to link from an article to the same article in a different product version. For example:
- You mention some functionality that is not available for free, pro, or team plans and you want to link to the GitHub Enterprise Cloud version of the same page.
- The GitHub Enterprise Server version of an article describes a feature that shipped with that version, but site administrators can upgrade to the latest version of the feature that's in use on GitHub Enterprise Cloud.
You can link directly to a different version of the page using the `currentArticle` property. This means that the link will continue to work directly even if the article URL changes.
```markdown
{% ifversion fpt %}For more information, see the [{% data variables.product.prodname_ghe_cloud %} documentation](/enterprise-cloud@latest/{{ currentArticle }}).{% endif %}
Sometimes you want to link to a Dotcom-only article in Enterprise content and you don't want the link to be Enterprise-ified. To prevent the transformation, you should include the preferred version in the path.
Sometimes the canonical home of content moves outside the docs site. None of the links included in [`src/redirects/lib/external-sites.json`](/src/redirects/lib/external-sites.json) get rewritten. See [`contributing/redirects.md`](/contributing/redirects.md) for more info about this type of redirect.
Our docs contain links that use legacy filepaths such as `/article/article-name` or `/github/article-name`. Our docs also contain links that refer to articles by past names. Both of these link types function properly because of redirects, but they are bugs.
When you add a link to an article, use the current filepath and article name.
Index pages are the Table of Contents files for the docs site. Every product, category, and map topic subdirectory has an `index.md` that serves as the landing page. Each `index.md` must contain a `children` frontmatter property with a list of relative links to the child pages of the product, category, or map topic.
**Important note**: The site only knows about paths included in `children` frontmatter. If a directory or article exists but is **not** included in `children`, its path will 404.
The homepage is the main Table of Contents file for the docs site. The homepage must have a complete list of `children`, like every [Index page](#index-page) but must also specify the `childGroups` frontmatter property that will be highlighted in the main content area.
`childGroups` is an array of mappings containing a `name` for the group, an optional `icon` for the group, and an array of `children`. The `children` in the array must be present in the `children` frontmatter property.
To create a product guides page (e.g. [Actions' Guide page](https://docs.github.com/en/actions/guides)), create or modify an existing markdown file with these specific frontmatter values:
