Examine source code of Safebook

{
  "name": "Safebook",
  "version": "1.2.0",
  "description": "Facebook without the content",
  "homepage_url": "https://bengrosser.com/projects/safebook/",
  "manifest_version": 2,
  "icons": {
    "32": "safebook-logo-32.png",
    "48": "safebook-logo-48.png",
    "64": "safebook-logo-64.png",
    "128": "safebook-logo-128.png",
    "256": "safebook-logo-256.png",
    "512": "safebook-logo-512.png"
  },
  "browser_action": {
    "default_icon": "safebook-logo-32.png",
    "default_popup": "options.html"
  },
  "permissions": [],
  "content_scripts": [
    {
      "run_at": "document_start",
      "matches": [
        "*://*.facebook.com/*"
      ],
      "all_frames": true,
      "exclude_globs": [
        "*://*.facebook.com/ai.php*",
        "*://*.facebook.com/ajax/*",
        "*://*.facebook.com/dialog/*",
        "*://*.facebook.com/xti.php*",
        "*://*.facebook.com/plugins/*",
        "*://*.facebook.com/connect/*"
      ],
      "exclude_matches": [
        "*://*.facebook.com/ai.php*",
        "*://*.facebook.com/ajax/*",
        "*://*.facebook.com/dialog/*",
        "*://*.facebook.com/xti.php*",
        "*://*.facebook.com/plugins/*",
        "*://*.facebook.com/connect/*"
      ],
      "css": [
        "safebook.css"
      ],
      "js": [
        "ready.js",
        "safebook.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "safebook@bengrosser.com",
      "strict_min_version": "57.0"
    }
  }
}