Bayesian inference of phylogeny is based upon a quantity called the posterior
probability distribution of trees, which is the probability of a tree
conditioned on the observations. The conditioning is accomplished using
Bayes's theorem. The posterior probability distribution of trees is
impossible to calculate analytically; instead, MrBayes uses a simulation
technique called Markov chain Monte Carlo (or MCMC) to approximate the
posterior probabilities of trees.
The package provides the debug symbols that are otherwise stripped from
the binaries to reduce the footprint of the package. This package can be
installed to help debugging of problems when running mrbayes.