Examine source code of Reddit Cat Filter

{
  "manifest_version": 2,
  "name": "Reddit Cat Filter",
  "version": "1.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "reddit-cat-filter@mathias.zillmann",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Filters out cat-related posts from Reddit",
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.reddit.com/*",
        "*://reddit.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "style.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  }
}