Examine source code of Localise Timezones

{
  "manifest_version": 2,
  "name": "Localise Timezones",
  "description": "Converts times to your local time zone",
  "version": "0.5.1",
  "icons": {
    "128": "icon-128.png",
    "512": "icon-512.png"
  },
  "browser_action": {
    "default_title": "Localise Timezones",
    "default_icon": {
      "128": "button.png"
    }
  },
  "options_ui": {
    "page": "options.html",
    "chrome_style": true
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "browser-polyfill.js",
        "core.js",
        "content.js"
      ],
      "all_frames": true,
      "run_at": "document_idle",
      "css": [
        "popup.css"
      ]
    }
  ]
}