Examine source code of Full Crosshair Cursor

{
  "manifest_version": 2,
  "name": "Full Crosshair Cursor",
  "version": "1.0.1",
  "description": "Full Crosshair Cursor over window",
  "icons": {
    "16": "src/icons/16.png",
    "48": "src/icons/48.png",
    "128": "src/icons/128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/app.js"
      ],
      "css": [
        "src/style.css"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ]
}