Frontmatter is an essential feature of Gatsby that provides extra data or configuration for content within a site. It enables a Gatsby site to be more dynamic and controlled with data coming from external sources or plugins. This feature is used in all sorts of ways such as configuring specific pages or posts, setting meta data, and enabling theming on a site.
Here are some of the more common uses of Frontmatter:
Global Configuration – Frontmatter can be used to set global configurations for a Gatsby site. This includes things like themes, topics, styles and even plugin configuration.
Data Sources – Frontmatter can be used to turn specific pieces of content into data sources, such as posts, pages, categories, tags, and so forth. Content in these data sources can then be queryable and used within other plugins or the site itself.
Meta Data – Frontmatter can be used to set meta data information such as page titles, dates and descriptions. These values can then be queried and set programmatically, removing the need for developers to manually set the data.
SEO – Frontmatter can be used to set search engine optimized meta data, such as titles and descriptions, for content sources. This will ensure your pages are properly indexed by search engines and appear in search results.
So, as you can see, Frontmatter is an essential feature of Gatsby that enables a lot of additional configuration and control of a Gatsby site. For more information about Frontmatter, please check out the Gatsby docs: https://www.gatsbyjs.org/docs/frontmatter/.