Examine source code of Holded Time Tracker

{
  "manifest_version": 2,
  "name": "Holded Time Tracker",
  "version": "1.0",
  "description": "Solves Holded's limitation by adding the current timer to your total worked time and updating it every minute",
  "permissions": [
    "activeTab",
    "tabs",
    "https://*.holded.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.holded.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "all_frames": true
    }
  ],
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "holded-time-tracker@example.com",
      "strict_min_version": "58.0"
    }
  }
}