Examine source code of URL Keyword Blocker

{
  "manifest_version": 2,
  "name": "site blocker",
  "version": "1.3.0",
  "description": "block whichever sites you want",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/32.png",
    "default_title": "site blocker",
    "default_popup": "popup/blocker.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "block.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{31a0e302-11b2-4ea9-ba2d-112a19c09832}"
    }
  }
}