The Custom Bitlinks section is where all of your branded and customized bitlinks will live as an Enterprise customers. To be considered a custom bitlink, it will need to have both a branded short domain (bsd) AND a customized backend.
For example, bit.ly/bitlinks would not be considered a custom bitlink because it does not have a branded short domain. es.pn/2yxklu would not be considered a custom bitlink because while it has a branded short domain, it doesn't have a customized backhalf. An example of a link that would live in this section is es.pn/SuperBowl