dca add command - guide?

I've picked up from a few posts that "dca add x xxxx/xxx/xxxxx.desktop" seems to be being used to add items to the desktop folders without having to edit the group-app.xml file manually.

Is there a simple reference guide for this? e.g. presumably each folder (Connect, Work, Fun, Files etc) has a reference number referred to in the script, it would be useful to know what they are.

Is dca a standard tool for xfce desktops?

Cheers!

Matt