On the surface, "12345" looks like a default combination (much like a luggage code). In the context of web proxies, users often append simple numeric strings to search queries for two reasons:
A web proxy acts as a middleman between your computer and the internet. When you use a proxy, your web requests are sent through the proxy server first, which then fetches the content for you. This allows you to:
While free proxies are convenient for quick tasks, they carry significant risks that a typically mitigates: ProxySite.com - Free Web Proxy Site
Your browsing history is often logged and sold to third parties to cover the server costs. 🟡 Medium