Hello,
Add-ons documentation links are broken with Blender 2.79 daily builds or 2.80 alpha.
Try:
Blender User preferences>Add-ons>
Expand the first add-on, click on Documentation link.
There is a redirection to :
https://wiki.blender.org/wiki/Extensions:2.6/Py/Scripts/3D_interaction/3D_Navigation
The correct link is:
https://en.blender.org/index.php/Extensions:2.6/Py/Scripts/3D_interaction/3D_Navigation
Could you do something for that?