Hi Andee,
Yes, there is still such a plugin. You can find it here under the Utilities tab. It’s called Attribute Stacker. Supposing you already have a CODAP document with the dataset you wish to restructure, you can either the embeddable link into that document, or copy its URL and import it into that document.
The situation the Attribute Stacker deals with is one in which you have a bunch of attributes you want to stack into child cases.
I hope that’s your situation and that it works for you. It’s not particularly user-friendly, and that’s why we haven’t put it into the builtin plugins menu. (But we’re working to change that!)
Bill