As said in short description, this add-on just adds a checkbox "I read and accept rules" with link to rules in content creation interface.
This can be used for forcing users read a rules for specific forum node before creating a thread, because button for creating a thread is disabled when checkbox is not set (e.g. when the user needs to accept the forum rules when creating an account).
Rules URL is set per node directly in node settings:
By default, add-on supports only forum nodes and resource nodes (XFRM is required).
All texts is placed in phrases, so you can customize text and translate to own language.
This add-on is published on GitHub.