Examine source code of Duh Autocorrection

{
  "manifest_version": 2,
  "name": "Duh",
  "description": "Auto-correct common misspellings in input fields",
  "version": "0.0.1",
  "permissions": [
    "storage",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Duh Settings",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e97456fe-3b23-4ddd-b6c3-8df8fe3304db}"
    }
  }
}