Examine source code of Javascript Bundle Size

{
  "manifest_version": 2,
  "name": "Javascript Bundle Size",
  "author": "Viktor Razumov",
  "description": "Automatically adds javascript bundle size data to npm and github project pages",
  "homepage_url": "https://github.com/vicrazumov/js-bundle-size",
  "version": "0.1.1",
  "content_scripts": [
    {
      "css": [
        "css/style.css"
      ],
      "js": [
        "js/content.js",
        "js/github-content.js"
      ],
      "matches": [
        "https://github.com/*/*"
      ]
    },
    {
      "css": [
        "css/style.css"
      ],
      "js": [
        "js/content.js",
        "js/npmjs-content.js"
      ],
      "matches": [
        "https://www.npmjs.com/package/*"
      ]
    }
  ],
  "icons": {
    "16": "/icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "https://bundlephobia.com/api/size"
  ]
}