Examine source code of Shortcut2Url

{
  "name": "Shortcut2Url",
  "description": "Shortcut2Url gives you 4 keyboard shortcuts for your favorite sites",
  "version": "2.0.2",
  "manifest_version": 2,
  "icons": {
    "16": "assets/images/icon-16.png",
    "48": "assets/images/icon-48.png",
    "128": "assets/images/icon-128.png"
  },
  "background": {
    "scripts": [
      "scripts/background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "options_ui": {
    "page": "views/options.html",
    "open_in_tab": true
  },
  "commands": {
    "1": {
      "suggested_key": {
        "default": "Ctrl+Shift+1",
        "mac": "Command+Shift+1"
      },
      "description": "Shortcut 1"
    },
    "2": {
      "suggested_key": {
        "default": "Ctrl+Shift+2",
        "mac": "Command+Shift+2"
      },
      "description": "Shortcut 2"
    },
    "3": {
      "suggested_key": {
        "default": "Ctrl+Shift+3",
        "mac": "Command+Shift+3"
      },
      "description": "Shortcut 3"
    },
    "4": {
      "suggested_key": {
        "default": "Ctrl+Shift+4",
        "mac": "Command+Shift+4"
      },
      "description": "Shortcut 4"
    }
  },
  "version_name": "2.0.2"
}