Examine source code of MozBar

{
  "manifest_version": 2,
  "name": "MozBar",
  "description": "SEO Toolbar by Moz",
  "version": "5.0.16",
  "icons": {
    "16": "/icon/16.png",
    "32": "/icon/32.png",
    "48": "/icon/48.png",
    "96": "/icon/96.png",
    "128": "/icon/128.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "activeTab",
    "webNavigation",
    "cookies",
    "https://api.moz.com/*",
    "https://stage.api.moz.com/*",
    "https://staging.api.moz.com/*",
    "https://development.api.moz.com/*",
    "https://lsapi.seomoz.com/*",
    "https://moz.com/*",
    "https://*.moz.com/*",
    "http://localhost/*"
  ],
  "optional_permissions": [
    "webRequest"
  ],
  "web_accessible_resources": [
    "icon/*.png",
    "assets/*",
    "content-scripts/toolbar.css"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "mozbar.firefox@moz.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "browsingActivity",
          "websiteActivity"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    },
    "safari": {
      "strict_min_version": "14.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "MozBar",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.bing.com/*",
        "*://*.duckduckgo.com/*",
        "*://*.google.ca/*",
        "*://*.google.co.uk/*",
        "*://*.google.com.au/*",
        "*://*.google.com/*",
        "*://*.search.yahoo.com/*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/content.js"
      ]
    },
    {
      "matches": [
        "*://*.bing.com/search*",
        "*://*.duckduckgo.com/*",
        "*://*.google.ca/search*",
        "*://*.google.co.jp/search*",
        "*://*.google.co.uk/search*",
        "*://*.google.com.au/search*",
        "*://*.google.com.br/search*",
        "*://*.google.com/search*",
        "*://*.google.de/search*",
        "*://*.google.es/search*",
        "*://*.google.fr/search*",
        "*://*.google.it/search*",
        "*://*.search.yahoo.com/*"
      ],
      "run_at": "document_idle",
      "css": [
        "content-scripts/serp.css"
      ],
      "js": [
        "content-scripts/serp.js"
      ]
    },
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/toolbar.js"
      ]
    }
  ]
}