Examine source code of Glitch this

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Glitch this",
  "description": "Glitch up webpages using CSS",
  "browser_specific_settings": {
    "gecko": {
      "id": "glitchThis@cubeleco"
    }
  },
  "browser_action": {
    "browser_style": true,
    "default_popup": "pages/popup.html",
    "default_icon": {
      "256": "icons/icon-256.png"
    }
  },
  "icons": {
    "256": "icons/icon-256.png"
  },
  "commands": {
    "_execute_browser_action": {
      "description": "Show popup"
    },
    "toggle": {
      "suggested_key": {
        "default": "Alt+G"
      },
      "description": "Toggle extension"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "defaults.js",
        "glitch.js"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "storage"
  ]
}