For each OS branch, there are two rotating sets of builds:
    -latest and -previous
    (misnamed -full for historical reasons).
  
    For certain branches, there are also experimental (-exp)
    builds, which are either regression tests, or release builds.
  
Although there are 5 architectures, there is not enough horsepower to build every branch on every architecture. Thus, the matrix is sparse (shown as of 201004):
This is a total of 34.