Examine source code of InFocus for Facebook

{
  "manifest_version": 2,
  "name": "Content Filter",
  "version": "1.2",
  "description": "Filter Facebook content by type",
  "permissions": [
    "storage",
    "activeTab",
    "*://*.facebook.com/*",
    "https://api.emailjs.com/*"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "scripts/core.js",
        "scripts/facebook.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "infocus@elias",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}