Examine source code of form-info

{
  "description": "Adds a form information panel to the developer tools.",
  "manifest_version": 2,
  "name": "form-info",
  "version": "0.2.8resigned1",
  "author": "Atsawin Chaowanakritsanakul",
  "homepage_url": "https://github.com/atsawin/form-info",
  "icons": {
    "48": "icons/form48.png"
  },
  "background": {
    "scripts": [
      "background_scripts/background.js"
    ]
  },
  "permissions": [
    "<all_urls>"
  ],
  "devtools_page": "devtools/devtools-page.html",
  "browser_specific_settings": {
    "gecko": {
      "id": "{78bd48e2-ef58-4742-9695-80631d3b41b7}"
    }
  }
}