Examine source code of Blocker

{
  "manifest_version": 2,
  "name": "Blocker",
  "version": "1.0",
  "description": "This AddOn blocks shock websites.",
  "icons": {
    "100": "icons/AddOnIcon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "addon@Blocker.com",
      "strict_min_version": "42.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "gretaBlocker.js"
      ]
    }
  ]
}