A GR group (basically a forum) can have "folders" of topics (basically different areas/sub-forums). When you look up a group, you will get a list of all folders, with the last 4 discussions for each folder; on a group with dozens of folders (e.g. the SciFi and Fantasy Book Club) it means you might have to scroll quite a bit to get the (small) link to the folder you're interested in.
So this script will make the folders "expandable", and collapse them by default if they are more than a certain amount (by default 2, but you can customize this threshold). Preview: