This Documentation was written for version 8.2.0 of the extension.
Only purpose is to render the reCAPTCHA and validate the response. But provide these to other extensions which consumes the service.
Also there are limited integrations into other extensions implemented. These act more as an living example and integrate only in extensions used by the author self.
As a very focused extension only the following features are integrated
service for display and validation
integration in form rendering of EXT:form
integration of invisible captcha in EXT:form
viewHelper for display in fluid templates
validator for usage in extbase domain model validation
adapter for in-/visible captcha in sf_register
adapter for in-/visible captcha in typoscript