Sorry for the inconvenience. Known Navigation header breakage, its being "rebuilt" but forward nav should be ok now.
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.
Translations:Tasks Looking for People/1/en
PC-BSD® is more than a cool operating system. It is a community of users, where each user is welcome to contribute their talents in order to constantly improve PC-BSD® and the PC-BSD® computing experience. The Handbook has many ideas to get you started in contributing to the PC-BSD® community.