Captcha is text spam filtering plugin. When saving or moving page plugin asks user simple question (What is the largest continent on earth?) - if correctly answered, page is saved/moved. Plugin is automatically deactivated when password protection is on.
Database of questions and answers is located in plugins/data/Captcha/. Format of the database is like this:
-- What color is lemon? Yellow -- How much is 4 times 4? 16, sixteen -- Fill missing: cat - Tom, mouse - Jerry
Next question is indicated by "--", second line is question and third line is list of possible correct answers separated by comma.
- $permanent - setting to true means that after correctly answering single question can then user edit without any further questions. Setting to false means that user has to correctly answer everytime (s)he wants to save or rename page.