Examine source code of Text Column Counter Panel

{
  "manifest_version": 2,
  "name": "Text Column Counter Panel",
  "version": "1.0.0",
  "description": "Count columns in each line based on a separator.",
  "browser_action": {
    "default_title": "Column Counter",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "text-column-counter-f5074aae-69e0-4a15-a088-700d56db4c70@example.com",
      "strict_min_version": "58.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}