get https://example.com/api/v1/wbs/work_item_quantities_query
Query APIs are any API endpoints that are suffixed with _query. These APIs differ from other APIs in that they offer pre-joined, and pre-normalized (flattened) results without the need to make multiple API calls to be joined and transformed in another system.
Query APIs are useful when trying to get results around a particular entity type such as Design Elements or Work Items.
As they are pre-joined they offer a very simply way of getting all the information related to those items, however this comes with the cost of an increased payload.
When using these queries, pay particular attention to the page size and field selection in order to control the total payload to improve performance.