It isn't on the web interface, go to the machine and login as admin, then...
Machine Status > Tools > Device Settings > General > Customer Keyboard Button and modify it to match
I have a client with 4 colorcubes 9303. On two of them, when they scan to email and enter an email address, they have the option to suffix the recipient email with "@theirdomainname.com" by pressing a single button with that label. On the other two, that button simple says ".com" (which I believe is the default value). So someone must have changed the value of that button at some point. However I have looking through the webinterface and simply cannot find that function anywhere. So my question to you: Where do I change the value of that button?