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