Examine source code of Chart

{
  "manifest_version": 2,
  "name": "Chart",
  "version": "1.0.0",
  "description": "Quickly sketch bar and line charts from raw data you type or paste. Copy the chart as an image or export the data.",
  "browser_specific_settings": {
    "gecko": {
      "id": "emtelam511@gmail.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "description": "All data entry and chart rendering happens entirely in-browser. No data leaves your device."
      }
    }
  },
  "permissions": [
    "clipboardRead",
    "storage"
  ],
  "browser_action": {
    "default_popup": "canvas/ui.html",
    "default_title": "Chart — Quick Data Sketch",
    "default_icon": {
      "16": "icons/chart-bar-16.png",
      "48": "icons/chart-bar-48.png",
      "96": "icons/chart-bar-96.png"
    }
  },
  "background": {
    "scripts": [
      "calc/background.js"
    ],
    "persistent": false
  }
}