Examine source code of Auto Reset Timer

{
  "manifest_version": 2,
  "name": "Auto Reset Timer",
  "version": "1.2.18.25",
  "description": "A simple countdown timer that auto-resets with customizable hotkeys.",
  "permissions": [
    "storage",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png",
      "48": "icon.png",
      "128": "icon.png"
    }
  },
  "commands": {
    "start-timer": {
      "suggested_key": {
        "default": "Alt+G"
      },
      "description": "Start/Stop timer"
    },
    "reset-timer": {
      "suggested_key": {
        "default": "Alt+R"
      },
      "description": "Reset the timer"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2e6d3c28-6099-40d8-bd57-93378247c962}"
    }
  }
}