manifest.json

{
	"manifest_version": 2,
	"name": "ChromeFill",
	"version": "0.1",
	"description": "Dynamically injects polyfills into sites to support newer JavaScript",
	"author": "InterLinked",
	"permissions": [
		"webRequest", // needed for modifying user agent
		"webRequestBlocking",
		"https://*/*",
		"http://*/*"
	],
    "content_scripts": [
		{
			"matches": [
				"https://github.com/*" // GitHub, at present, insists on using the evil nullish coalescing and optional chaining
				// Add other sites here that use evil nullish coalescing and optional chaining. If we can get by with just polyfills, don't transpile.
				// Avoid transpiling except as a last resort, because it's SLOW and blocking, not to mention VERY memory and CPU intensive
				// e.g. GitHub takes 15 seconds on my machine to transpile
			],
			"js": [
				"babel.min.js"
			],
			"run_at": "document_start",
			"all_frames": true
		},
		{
			"matches": [
				"https://*/*",
				"http://*/*"
			],
			"js": [
				"polyfills.js"
			],
			"run_at": "document_start",
			"all_frames": true
		}
	],
	"background": {
		"scripts": [
			"useragent.js"
		],
		"persistent": true
    },
	"icons": {
		"16": "images/icon16.png",
		"32": "images/icon32.png",
		"48": "images/icon48.png",
		"128": "images/icon128.png"
	}
}