Examine source code of SwapFace Meme-er

{
  "manifest_version": 2,
  "name": "SwapFace Meme-er",
  "version": "1.0",
  "description": "Detect faces in images and swap with famous meme faces like Thanos or Shrek.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1fca7bda-8095-4222-8736-19e306140417}"
    }
  }
}