Examine source code of mediaBlock

{
  "manifest_version": 2,
  "version": "0.0.1.9",
  "default_locale": "en",
  "name": "mediaBlock",
  "description": "Disable all images and block unwanted website for one week. Import Blocklists",
  "icons": {
    "128": "icons/icon128.png"
  },
  "permissions": [
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "storage",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/icon128.png",
    "default_title": "mediaBlock",
    "default_popup": "popup.html",
    "browser_style": true
  },
  "web_accessible_resources": [
    "pages/blocked.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a4caa6b8-dfb6-426b-b7d9-9fbec232a26c}"
    }
  }
}