Examine source code of Page Pen & Capture Pro

{
  "manifest_version": 2,
  "name": "Page Pen & Capture Pro",
  "version": "2.0.1",
  "description": "Draw on any page, add arrows/text, erase, capture selected areas, copy to clipboard, and save visible or full-page screenshots.",
  "permissions": [
    "activeTab",
    "tabs",
    "downloads",
    "clipboardWrite",
    "storage",
    "<all_urls>"
  ],
  "background": {
    "page": "background.html",
    "persistent": true
  },
  "browser_action": {
    "default_title": "Toggle Page Pen"
  },
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "commands": {
    "toggle-drawing": {
      "suggested_key": {
        "default": "Alt+D"
      },
      "description": "Toggle drawing mode"
    },
    "select-screenshot": {
      "suggested_key": {
        "default": "Alt+S"
      },
      "description": "Start area screenshot mode"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "page-pen-capture-pro@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}