Free (科学上网) Proxy is a handy add-on that let you easily mask your real internet protocol (IP) address.
You can now browser under this socks5 proxy and mask your real ip address. Please note that, the API for searching proxies is free but only releases 20 results per day. Once the limit is over, the addon will only uses the proxies from its memory (previously saved ip and ports). In order to turn off the addon, please click on the top right button in the toolbar popup UI (grey icon).
Note: Free (科学上网) Proxy add-on does NOT store your IP address or any other information in any remote location. However, third-party services(mentioned above) have their own policy and rules for storing IP addresses.
If you have a feature request, or found a bug to report, please fill the bug report form in the addon's homepage (http://mybrowseraddon.com/private-network.html).