Manage Categories From Self Service Portal
You can see all the custom websites/Domains single/multiple as well as there respective custom single/multiple category from here.
As soon as you click on any particular custom category there respective websites/Domains should display.
Also there is a download option at the top of Category.After clicking on download all the categories from below list should get download.
Check website category
Upload multiple(bulk) websites
Monitor Custom Categories and Respective websites
For more detail or use of this feature follow link :