Examine source code of Layout Grid Overlay

{
  "manifest_version": 2,
  "name": "Layout Grid Overlay",
  "description": "Lay a column grid, a baseline grid and element outlines over any page. Set the column count, gutter, content width and margins, and keep a different setup per site.",
  "version": "5.3.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "{6f57da9e-b334-47e2-a2a6-21ea45369ad0}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "browser_action": {
    "default_title": "Layout Grid Overlay",
    "default_popup": "popup.html",
    "default_icon": {
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png"
    }
  },
  "permissions": [
    "activeTab",
    "storage"
  ]
}