Examine source code of Environment Indicator

{
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "1.0.3",
  "manifest_version": 2,
  "default_locale": "en",
  "icons": {
    "16": "icons/icon-16x16.png",
    "48": "icons/icon-48x48.png",
    "128": "icons/icon-128x128.png"
  },
  "browser_action": {
    "default_popup": "www/index.html#/popup",
    "default_title": "__MSG_extensionName__"
  },
  "background": {
    "scripts": [
      "www/js/bex-background.js",
      "js/background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "www/js/bex-content-script.js",
        "js/content-script.js"
      ],
      "css": [
        "css/content-css.css"
      ]
    }
  ],
  "options_page": "www/index.html",
  "permissions": [
    "storage"
  ],
  "web_accessible_resources": [
    "www/*",
    "js/*",
    "css/*",
    "<all_urls>"
  ],
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self';",
  "applications": {
    "gecko": {
      "id": "gaoliangim@gmail.com",
      "strict_min_version": "53.0"
    }
  }
}