Sorry for the inconvenience. Known Navigation header breakage, its being "rebuilt."
There may be other unforeseen breakage primarily in the handbook portion of the wiki.
The Table Of Contents section of each "PC-BSD® Users Handbook" page may be the best workaround.
To view or manually configure all of your network interfaces click Control Panel → Network Configuration or type pc-su pc-netmanager. If a new device has been inserted (e.g. a USB wireless interface), a pop-up message will open when you start Network Configuration, indicate the name of the new device, and ask if you would like to enable it. Click Yes and the new device will be displayed with the list of network interfaces that PC-BSD® recognizes. In the example seen in Figure 8.16b, the system has one Realtek Ethernet interface that uses the em driver and a wireless interface that uses the wlan driver.