Examine source code of Close Duplicate Tabs

{
  "author": "igorlogius",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_area": "navbar"
  },
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{4ff5fdbd-64eb-4c8c-89f0-ee8245ad322a}"
    }
  },
  "commands": {
    "_execute_browser_action": {}
  },
  "description": "Displays the number of duplicate tabs and allows to quickly to close the left most ones while leaving the right most intact",
  "homepage_url": "https://github.com/igorlogius/webextensions/tree/main/sources/close-duplicate-tabs",
  "icons": {
    "128": "icon.png"
  },
  "manifest_version": 2,
  "name": "Close Duplicate Tabs",
  "permissions": [
    "cookies",
    "tabs"
  ],
  "version": "1.0.33"
}