The main part of the customized short link (mixed link) is a branded domain. It is a customized domain which can be purchased for yourself or your business, to use for all your shared links.
For example, 'short.cm' is the branded domain in short.cm/users/dashboard/settings link.
The main purpose of a branded domain is to increase the confidence and brand recognition. Finally it will help you to improve brand engagement of your shared links.