Replace / offer alternatives to reCaptcha.

Why there should be alternative(s) to reCaptcha:

1. I solved reCaptcha for 2 minutes as a punishment of using Firefox and privacy-enhancing add-ons. This totalled the creation of a test account to 3 minutes. Open-Sourcerers and/or developers are likely to have a similar setup to me. This is terrible UX.

2. There's news, that reCaptcha will no longer be free and Cloudflare, the biggest reCaptcha client, will be switching to hCaptcha.

3. I don't remember. I'll edit this when I do. Well consider that I have been writing this for 18 minutes a good enough reason.

Useful sources:

• Riot.im has been considering open-source / less-evil alternatives for 2 years now.

• awesome-captcha awesome-list.