This is the first beta of the Freeciv 3.2 series.
For an overview of what's changed since 3.1.x, see https://www.freeciv.org/wiki/NEWS-3.2.0, or the NEWS file in the source archive.
The archive freeciv-graphics-materials-3.2.0-beta1.tar.xz contains material such as 3D models originally used to prepare Freeciv's graphics, as a reference for anyone wishing to modify them. It is distributed separately due to its size, and is not required to build Freeciv from source.