Examine source code of Merge Windows

{
  "permissions": [
    "tabs",
    "contextMenus"
  ],
  "description": "Merge all tabs into the current window",
  "homepage_url": "https://github.com/MykBamberg/merge-windows",
  "manifest_version": 2,
  "name": "Merge Windows",
  "version": "1.0.1",
  "icons": {
    "96": "merge.svg"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "merge-windows": {
      "suggested_key": {
        "default": "Alt+M"
      },
      "description": "Merge all tabs into the current window"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{306795e8-3575-4dba-82d9-5da615b7aa24}"
    }
  }
}