Examine source code of Visit History

{
  "manifest_version": 2,
  "name": "Visit History",
  "version": "1.1",
  "author": "Rob Hoelz",
  "description": "Shows your first and most recent visit to a page",
  "page_action": {
    "browser_style": true,
    "default_icon": "icons/clock.svg",
    "default_title": "Most recent visit",
    "default_popup": "popup.html",
    "show_matches": [
      "<all_urls>"
    ]
  },
  "permissions": [
    "history",
    "tabs"
  ]
}