- Added a path `/header?key=` to `agnhost netexec` allowing one to view what the header value is of the incoming request.

  Ex:
  ```

- If the user specifies an invalid timeout in the request URL, the request will be aborted with an HTTP 400.

- Added ListMeta.RemainingItemCount. When responding to a LIST request, if the server has more data available, and if the request does not contain label selectors or field selectors, the server sets the ListOptions.RemainingItemCount to the number of remaining objects. ([#75993](https://github.com/kubernetes/kubernetes/pull/75993), [@caesarxuchao](https://github.com/caesarxuchao))

	    * The new metrics are:

	    * cloudprovider_gce_api_request_duration_seconds{request, region, zone}

	    * cloudprovider_gce_api_request_errors{request, region, zone}

	    * request is the specific function that is used.

	    * region is the target region (Will be "<n/a>" if not applicable)

  // DefaultRequest is the default resource requirement request value by resource name if resource request is omitted.
  // +optional
  map<string, k8s.io.apimachinery.pkg.api.resource.Quantity> defaultRequest = 5;

- If the user specifies an invalid timeout in the request URL, the request will be aborted with an HTTP 400.

  - apiserver_flowcontrol_request_wait_duration_seconds 
  - apiserver_flowcontrol_current_executing_seats
  - apiserver_flowcontrol_nominal_limit_seats
  - apiserver_flowcontrol_rejected_requests_total
  - apiserver_flowcontrol_dispatched_requests_total
  - apiserver_flowcontrol_current_inqueue_requests

* Requests with the query parameter `?watch=` are treated by the API server as a request to watch, but authorization and metrics were not correctly identifying those as watch requests, instead grouping them as list calls. ([#48583](https://github.com/kubernetes/kubernetes/pull/48583), [@smarterclayton](https://github.com/smarterclayton))

  - `priority_level_request_count_samples` is replaced with `priority_level_request_utilization`, which samples every nanosecond rather than every millisecond; the old metric conveyed utilization despite its name.
  - `priority_level_request_count_watermarks` is removed.

* WATCHLIST calls are now reported as WATCH verbs in prometheus for the apiserver_request_* series.  A new "scope" label is added to all apiserver_request_* values that is either 'cluster', 'resource', or 'namespace' depending on which level the query is performed at. ([#52237](https://github.com/kubernetes/kubernetes/pull/52237), [@smarterclayton](https://github.com/smarterclayton))...