This repository configuration is intended to make ONLYOFFICE installation process easier and avoid entering several commands, replacing them with a single one.
Instead of adding GPG key and creating the onlyoffice.repo file manually, use the following command to add ONLYOFFICE repository on CentOS and derivatives
sudo yum install http://download.onlyoffice.com/repo/centos/main/noarch/onlyoffice-repo.noarch.rpm
After that you can continue ONLYOFFICE installation, as described here: