Examine source code of Third Sight

{
  "manifest_version": 2,
  "name": "Third Sight",
  "version": "0.2.1",
  "description": "Browsing history with thumbnails",
  "icons": {},
  "permissions": [
    "<all_urls>",
    "sessions",
    "webNavigation"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "browser_style": true,
    "default_icon": "icon.svg",
    "default_title": "Show history with thumbnails",
    "default_popup": "index.html",
    "show_matches": [
      "<all_urls>"
    ]
  }
}