Examine source code of RecenTabs

{
  "manifest_version": 2,
  "name": "recentabs",
  "description": "Direct access to recently closed tabs.",
  "version": "1.0.1",
  "icons": {
    "16": "icons/recentabs16.png",
    "32": "icons/recentabs32.png",
    "64": "icons/recentabs64.png",
    "128": "icons/recentabs128.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_title": "RecentTabs",
    "default_popup": "dist/index.html"
  },
  "permissions": [
    "sessions",
    "tabs"
  ]
}