Who is this for?
People browsing the web over Tor but not with the Tor Browser
What does this do?
Less technical explanation
Cloudflare lets Tor Browser users in CAPTCHA-free while requiring a CAPTCHA for all other Tor connections. This extension emulates some of the Tor Browser's behavior (you won't notice this) to trick Cloudflare into thinking you use the Tor Browser.
Note: It seems that newer versions of Firefox don't need this add-on anymore to pass CAPTCHA-free on websites behind Cloudflare. It is recommended to uninstall this extension and, unless edge cases are found, the extension will be removed from the store. If you still have a use-case for it, open an issue or download it from the GitHub repository.
Technical explanation
Cloudflare uses the "alt-svc" HTTP header to transparently redirect Tor users to its own hidden service (which it calls "Cloudflare Onion Services"). If accessed over this service, users are not required to complete a CAPTCHA to see a Cloudflare-protected website.
Unfortunately, Cloudflare only sends the alt-svc header if it thinks the request comes from the Tor Browser, even though other browsers are also capable of using Tor via a proxy. This extension adjusts Firefox's request behavior (in particular the headers) to look more like the Tor Browser, so that Cloudflare sends the alt-svc header and no one has to bother with CAPTCHAs anymore.
Note that this extension can't prevent all CAPTCHAs. Website administrators can choose to disable the Cloudflare mechanism that enables this. You would also see a CAPTCHA over the Tor Browser in that case.
Links
- AMO: https://addons.mozilla.org/en-US/firefox/addon/onionflare
- GitHub: https://github.com/T0astBread/onionflare
Attribution
The icon is made of several photos created by other people: