Examine source code of Tab Focus

{
  "manifest_version": 2,
  "name": "Tab Focus",
  "version": "4.1",
  "description": "Prevent selected tabs from detecting when you switch away.",
  "permissions": [
    "tabs",
    "storage",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "tabfocus@local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Tab Focus",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "commands": {
    "toggle-current-tab": {
      "suggested_key": {
        "default": "Alt+Shift+F"
      },
      "description": "Toggle Tab Focus on current tab"
    },
    "cycle-mode": {
      "suggested_key": {
        "default": "Alt+Shift+M"
      },
      "description": "Cycle spoof mode on current tab"
    }
  }
}