leave unused rules in iptables for a while (up to `--iptables-sync-period`)
  before deleting them. This improves performance by not requiring it to
  check for stale rules on every sync. (In smaller clusters, it will still
  remove unused rules immediately once they are no longer used.)

  (The threshold for "large" used here is currently "1000 endpoints" but

- Dockershim security: pod sandbox now always run with `no-new-privileges` and `runtime/default` seccomp profile
  dockershim seccomp: custom profiles can now have smaller seccomp profiles when set at pod level ([#90948](https://github.com/kubernetes/kubernetes/pull/90948), [@pjbgf](https://github.com/pjbgf)) [SIG Node]

- Refactored `test/e2e/framework` so that the core framework is smaller. Optional functionality like resource monitoring, log size monitoring, metrics gathering and debug information dumping must be imported by specific e2e test suites. Init packages are provided which can be imported to re-enable the functionality that...

### SIG Network

For 1.13, the areas of focus were in IPv6, DNS improvements and some smaller items:
CoreDNS is now the default cluster DNS passing all of the scale/resource usage tests

* Fixes validation of VolumeAttachment API objects created with inline volume sources. ([#80945](https://github.com/kubernetes/kubernetes/pull/80945), [@tedyu](https://github.com/tedyu))
* Fix kubelet errors in AArch64 with huge page sizes smaller than 1MiB ([#78495](https://github.com/kubernetes/kubernetes/pull/78495), [@odinuge](https://github.com/odinuge))

    * PodOverhead is an alpha feature as of Kubernetes 1.16.
* Fix kubelet errors in AArch64 with huge page sizes smaller than 1MiB ([#78495](https://github.com/kubernetes/kubernetes/pull/78495), [@odinuge](https://github.com/odinuge))