Examine source code of Big Day Timer

{
  "manifest_version": 2,
  "name": "Big Day Timer",
  "description": "Never lose track of an important date: clean countdown list with today/tomorrow highlighting and a persistent badge counter.",
  "version": "3.3.1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "{489490f1-f460-46db-8969-e47afd9b6d5b}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "core/core.js",
      "core/background.js"
    ]
  },
  "browser_action": {
    "default_title": "Big Day Timer",
    "default_popup": "core/popup.html",
    "default_icon": {
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png",
      "96": "icons/icon-96.png",
      "128": "icons/icon-128.png"
    }
  }
}