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.
pciconf -lv | grep wireless device = 'Realtek RTL8191SE wireless LAN 802.11N PCI-E NIC (RTL8191SE ?)'}}