Examine source code of Treestyle Tab Count

{
  "manifest_version": 3,
  "name": "Treestyle Tab Count",
  "version": "1.2",
  "description": "Adds a numeric tab count to each tab when using Tree Style Tab.",
  "icons": {
    "64": "icons/icon-64.png"
  },
  "action": {
    "default_icon": {
      "64": "icons/icon-64.png"
    },
    "default_popup": "pageAction/index.html",
    "default_title": "Treestyle Tab Count"
  },
  "background": {
    "scripts": [
      "background_script.js"
    ]
  },
  "permissions": [],
  "host_permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "treestyletabcount@zersche.local",
      "strict_min_version": "109.0"
    }
  }
}