Classes
A class is who a group-scoped event is about. A static class keeps a list you add to; a dynamic class holds whoever's attributes contain its filter, so nobody keeps it up. Beside the classes somebody keeps are temporary lists, picked by a person for one send: you can see them, but a key cannot change one and an event cannot name one. In the High school pack a class is, for example, “5A”.
GETList classes
Requires groups:read. Returns a bare JSON array, by name. Temporary lists are left out unless you ask for them with temporary=true: an event cannot name one, so a system choosing a group_id is better off never seeing them.
200 with an array of classes. An empty array when nothing matches.
A bare JSON array. Each item is one class: the same fields in every pack. Press Response on the sample to see one whole.
On failure the body is { error, code } instead.