Examine source code of SafeWeb.app

{
  "name": "SafeWeb.app",
  "version": "2.1",
  "manifest_version": 2,
  "description": "Allow access to safe links based on whitelist or block dangerous links based on blacklist.",
  "icons": {
    "16": "assets/icons/icon-16.png",
    "128": "assets/icons/icon-128.png"
  },
  "web_accessible_resources": [
    "assets/icons/*"
  ],
  "default_locale": "en",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ],
    "persistent": true
  },
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "youtube_embed",
        "enabled": false,
        "path": "assets/url-blocker/youtube_embed.json"
      }
    ]
  },
  "permissions": [
    "tabs",
    "storage",
    "declarativeNetRequest"
  ],
  "browser_action": {
    "default_icon": {
      "16": "assets/icons/icon-16.png",
      "48": "assets/icons/icon-48.png"
    },
    "default_title": "SafeWeb.app",
    "default_popup": "popup/index.html"
  },
  "applications": {
    "gecko": {
      "id": "qa@safeweb.app"
    }
  }
}