Examine source code of Toggl Track: Productivity & Time Tracker

{
  "version": "4.11.15",
  "browser_specific_settings": {
    "gecko": {
      "id": "toggl-button@toggl.com",
      "strict_min_version": "58.0"
    }
  },
  "name": "Toggl Track: Productivity & Time Tracker",
  "short_name": "Toggl Track",
  "manifest_version": 3,
  "description": "Puts a timer into any web tool and allows quick real time productivity tracking with all the data stored on your Toggl account",
  "background": {
    "scripts": [
      "sw.js"
    ]
  },
  "action": {
    "browser_style": false,
    "default_icon": {
      "19": "images/icon-19.png",
      "38": "images/icon-38.png"
    },
    "default_popup": "src/pages/popup/index.html",
    "default_title": "Toggl Time Tracker"
  },
  "commands": {
    "quick-start-stop-entry": {
      "suggested_key": {
        "default": "Ctrl+Shift+E"
      },
      "description": "Quick start/stop current entry"
    }
  },
  "icons": {
    "16": "images/icon-16.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  },
  "options_ui": {
    "page": "settings.html",
    "open_in_tab": true
  },
  "permissions": [
    "activeTab",
    "alarms",
    "contextMenus",
    "notifications",
    "scripting",
    "idle",
    "storage",
    "unlimitedStorage"
  ],
  "optional_permissions": [
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>",
    "*://*.toggl.com/*",
    "*://toggl.com/*"
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "settings.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    },
    {
      "resources": [
        "worker_proxy.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    },
    {
      "resources": [],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}