Let's build a web app manifest with Gatsby.

Gatsby Manifest Plugin

Using the plugin gatsby-plugin-manifest, add to gatsby-config.js

{
    resolve: `gatsby-plugin-manifest`,
    options: {
        name: `John Vincent`,
        short_name: `John Vincent`,
        start_url: `/`,
        background_color: `#ffffff`,
        theme_color: `#ffffff`,
        display: `standalone`,
        orientation: `landscape`,
        icon: `src/images/site/Cloud.jpg`, // This path is relative to the root of the site.
        cache_busting_mode: `none`,
    },
},

which generates file manifest.webmanifest