Corbonio repo for Rocky Linux/CentOS?

I'm trying to install Corbino CE to test it out before I migrate to it from Zimbra but the email that I got contains only Ubuntu repo info.

According to docs, there is an RPM repo somewhere. Anyone can point me in the right direction?

The whole site is very confusing and don't have or very hard to find any links to actual documentation and this forum, very strange.

Thank you in advance.