we are building 2.18 docs now too, and put them in website and docs site:
http://docs.qgis.org/testing (docs for QGIS 3.x to be) is also build.
Both untranslated untill 2.18 will be LTR (and later 3.2 will be...)
If you see something is wrong (like links, or notions of other versions
then 2.18) please let me now ( already fixed? see:
Like testing docs these will be rebuild twice a day.