Novell GroupWise 2012
Send yourself a HTML formatted mail where inside a message body you type several number strings. After you receive the mail and open it, many of the number strings are hyper-linked. When you hover over the link, at the bottom of the message you see tel:<number>.
If you do not want to have any telephony integration with a GroupWise 2012 client, simply go into Tools | Options | Environment icon. Then click on the Default Actions tab and find the "Default telephony provider" section. Here change it into None and save the change.
After that if you re-open the same mail, all numbers that were showing before a hyperlink look like normal numbers again.