Examine source code of ShortcutURL-Opener

{
  "manifest_version": 2,
  "name": "URL Opener",
  "version": "1.2",
  "description": "Open a specific URL with a shortcut.",
  "permissions": [
    "activeTab",
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ],
    "persistent": false
  },
  "commands": {
    "open-url-1": {
      "suggested_key": {
        "default": "Ctrl+1",
        "mac": "Command+1"
      },
      "description": "Open a specific URL"
    },
    "open-url-2": {
      "suggested_key": {
        "default": "Ctrl+2",
        "mac": "Command+2"
      },
      "description": "Open a specific URL"
    },
    "open-url-3": {
      "suggested_key": {
        "default": "Ctrl+3",
        "mac": "Command+3"
      },
      "description": "Open a specific URL"
    },
    "open-url-4": {
      "suggested_key": {
        "default": "Ctrl+4",
        "mac": "Command+4"
      },
      "description": "Open a specific URL"
    },
    "open-url-5": {
      "suggested_key": {
        "default": "Ctrl+5",
        "mac": "Command+5"
      },
      "description": "Open a specific URL"
    },
    "open-url-6": {
      "suggested_key": {
        "default": "Ctrl+6",
        "mac": "Command+6"
      },
      "description": "Open a specific URL"
    },
    "open-url-7": {
      "suggested_key": {
        "default": "Ctrl+7",
        "mac": "Command+7"
      },
      "description": "Open a specific URL"
    },
    "open-url-8": {
      "suggested_key": {
        "default": "Ctrl+8",
        "mac": "Command+8"
      },
      "description": "Open a specific URL"
    },
    "open-url-9": {
      "suggested_key": {
        "default": "Ctrl+9",
        "mac": "Command+9"
      },
      "description": "Open a specific URL"
    }
  },
  "browser_action": {
    "default_popup": "src/popup.html",
    "default_icon": {
      "16": "images/icon.png",
      "48": "images/icon.png",
      "128": "images/icon.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9e2dda9e-493b-4d08-9faf-e8a855a03118}"
    }
  }
}