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.