Installing Mesquite Packages
Mesquite comes with many "packages" already installed. A package is a collection of features that are related in terms of their functions. For example, the Align package that comes with Mesquite has numerous features for doing basic alignments, and supplies Mesquite with many of the manual and some automated alignment tools that are present in the matrix editor.
However, there are additional packages that do not come with a basic Mesquite installation, and that must be installed separately. See the page on additonal packages.