Examine source code of CSS Edit

{
  "manifest_version": 2,
  "name": "css editor",
  "version": "0.5",
  "description": "Real-time CSS injector with presets",
  "browser_specific_settings": {
    "gecko": {
      "id": "css-editor@keyser",
      "strict_min_version": "79.0"
    }
  },
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "popup/index.html",
    "default_title": "css editor",
    "default_icon": {
      "48": "icons/icon48.png",
      "96": "icons/icon96.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/injector.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "import.html",
    "import.js"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ],
    "persistent": false
  },
  "commands": {
    "toggle-site-styles": {
      "suggested_key": {
        "default": "Alt+Shift+S"
      },
      "description": "Toggle CSS for the current site"
    }
  }
}