Examine source code of Tomato Timer Quick Access

{
  "manifest_version": 2,
  "name": "Tomato Timer Quick Access",
  "version": "1.0",
  "description": "Quickly open Tomato Timer.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Open Tomato Timer",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ssemugg.a.su.l.a4.6@gmail.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "activeTab"
  ]
}