RSF Censorship Detector is a free Chrome add-on developed by the chrome-plugins-dev-Group. It falls under the category of Browsers and specifically, Add-ons & Tools. This program aims to help users access blocked websites by utilizing a unique strategy called "Collateral Freedom."

The RSF operation #CollateralFreedom tackles technological censorship by creating "mirrors" or duplicates of censored websites on top cloud service servers. This prevents authoritarian regimes from blocking access to the mirrors without restricting their own access to these cloud services. The RSF Censorship Detector extension simplifies the process of accessing mirrored versions of blocked websites. It adds an icon that turns red when a mirror is available, allowing users to click and gain access to the website, providing them with more freedom.

In order to keep up with changing URLs, the extension automatically updates itself when a mirror becomes inaccessible in a particular country. These mirrors are hosted by third-party CDNs like Cloudfront and fastly, ensuring reliable access to blocked content.