Examine source code of Trello Card Checker

{
  "manifest_version": 3,
  "name": "Trello Card Checker",
  "version": "2.6",
  "description": "Checks Trello cards for expired or soon-to-expire tasks.",
  "icons": {
    "40": "icons/icon_40px.png",
    "80": "icons/icon_80px.png"
  },
  "permissions": [
    "alarms",
    "notifications",
    "storage",
    "activeTab"
  ],
  "host_permissions": [
    "https://api.trello.com/"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_icon": "icons/icon_80px.png",
    "default_title": "Trello Due Date Checker",
    "default_popup": "index.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "TrelloDueDateChecker@kdani.ch",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}