Examine source code of Tab Merger

{
  "manifest_version": 2,
  "name": "Tab Merger",
  "version": "1.0",
  "description": "Merge all tabs from all windows into the current window.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/border-48.png",
    "default_title": "Merge Tabs"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4ff1434a-1678-41f4-bbc9-70d73f70b669}"
    }
  }
}