Examine source code of Focus Blocker Extension

{
  "manifest_version": 3,
  "name": "Focus Blocker",
  "version": "1.22",
  "description": "Firefox may be blocked if this extension is disabled or removed during a locked block.",
  "icons": {
    "16": "FocusBlockerIcon.png",
    "24": "FocusBlockerIcon.png",
    "32": "FocusBlockerIcon.png"
  },
  "content_scripts": [
    {
      "run_at": "document_start",
      "all_frames": true,
      "js": [
        "content.js"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "nativeMessaging",
    "tabs",
    "idle",
    "storage",
    "notifications",
    "alarms"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "focus@focusblocker.com",
      "strict_min_version": "109.0"
    }
  },
  "web_accessible_resources": [
    {
      "resources": [
        "blocked.html",
        "blocked.js",
        "permissions.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "action": {
    "default_icon": {
      "16": "FocusBlockerIcon.png",
      "24": "FocusBlockerIcon.png",
      "32": "FocusBlockerIcon.png"
    },
    "default_popup": "popup.html"
  }
}