Retrieve a single user group by its numeric id, with all of its settings.

When to use. Read one group's full configuration, for example before updating it or before listing its assigned users and campaigns. Returns 404 if the id does not exist.

Parameters. fields (optional): a semicolon-separated list of fields to return, for example description;ratio. When omitted, all available fields are returned.

Returns. { "groups": [ <group> ] }.

Example. GET /api/groups/5

{
  "groups": [
    {
      "id": 211,
      "name": "2024 Training Group"
    }
  ]
}