Examine source code of Focus Mode

{
  "manifest_version": 2,
  "name": "Focus Mode",
  "version": "1.0.0",
  "description": "Block distracting websites and set focused work sessions with customizable timers",
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "tabs",
    "<all_urls>",
    "notifications"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "web_accessible_resources": [
    "blocked.html",
    "blocked.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "872850469d48af51baedee8905c410d043f72c3d@extension.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}