How KMeans clustering works in Mahout 0.8?

[Saeed Adel Mehraban]

I read Mahout KMeans Design of implementation and it seems to be clear wrt
map-reduce paradigm. But when I refer to source code, I can not find the
mapper, reducer, combiner or almost anything mentioned in the official
website. What happened here and what I need to do to understand KMeans
implementation of Mahout?