Examine source code of History Navigate

{
  "manifest_version": 2,
  "name": "History Navigate",
  "version": "2.2.2",
  "description": "Allows navigate by history from context menu",
  "homepage_url": "https://github.com/vycb/HistoryNavigate",
  "icons": {
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "contextMenus",
    "history",
    "tabs",
    "activeTab",
    "menus",
    "<all_urls>",
    "webNavigation"
  ]
}