Examine source code of Time Limiter

{
  "manifest_version": 2,
  "name": "Time Limiter",
  "version": "1.2.5",
  "description": "Monitor And Limit the time you spend on websites and in total. Allows for custom break time. Open Source",
  "icons": {
    "48": "limiter-icon.svg",
    "96": "limiter-icon.svg"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "time-limiter@limitlost.com",
      "strict_min_version": "58.0"
    }
  },
  "background": {
    "scripts": [
      "helpers.js",
      "settings.js",
      "message.js",
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "helpers.js",
        "settings.js",
        "message.js",
        "main.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "global.css",
    "internal.css",
    "panel.html",
    "break-panel.html",
    "break-internal.css"
  ]
}