This package has data structures for representing simplicial meshes and algorithms for improving the quality of these meshes. See the The Five Essential Ingredients of Mesh Optimization page for an introduction to mesh optimization.
The documentation is distributed among a number of pages: There is brief overview and a discussion of the organization of the code. Another page gives more details on the data structures. There are many example programs which provide useful functionality and show how to use this package. Finally, there are a number of pages that show results of using the example programs.