So this binding has not been merged/accepted, hence why the wiki page is not on the main site. We do have a page, its at
https://github.com/digitaldan/openhab/tree/harmony-pr/bundles/binding/org.openhab.binding.harmonyhub. As soon as this is merged, I will post it up on the main site.
There is a huge list of PRs that Thomas and Kai need to review, so I don't know when this will be merged in.
Let me know if your questions are not answered after looking at the official readme, the io package provides methods that can be called in rules.
In the meantime I would appreciate if you would remove the wiki page, I will put the contents of the readme up once its appropriate and cloudbees starts generating packages people can download.
Thanks!