Examine source code of Show Visits

{
  "author": "igorlogius",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "128": "icon.png"
  },
  "manifest_version": 2,
  "name": "show-visits",
  "page_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "show_matches": [
      "<all_urls>"
    ]
  },
  "permissions": [
    "activeTab",
    "history"
  ],
  "version": "1.1.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "{22f55d44-5930-4dc6-893c-46da45fd4efa}"
    }
  }
}