Network Extension

1. Wi-Fi management

   Covers Wi-Fi configuration, Configuring a Wi-Fi accessory to join a network, Hotspot helper.

2. Virtual private networks

   Covers Routing your VPN network traffic, Personal VPN, Packet tunnel provider, App proxy provider.

3. Network relays

   Covers Relays.

4. Content filters

   Covers Content filter providers, Filtering Network Traffic.

5. URL filters

   Covers URL filters.

6. DNS configurations

   Covers DNS settings, DNS proxy provider.

7. Local networking

   Covers Local push connectivity.

8. App extensions

   Covers NEAppExtensionConfiguration.

9. Protocols

   Covers NEAppProxyUDPFlowHandling.

10. Structures

    Covers NETunnelProviderError, NEVPNError.

11. Variables

    Covers NERelayClientErrorDomain.

12. Enumerations

    Covers NERelayManagerClientError.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.