Most of the TE modules are available in different assembly options. Assembly option with different FPGA/SOC devices or other DDR sizes need an own board part file. In some cases also a revision change or a special carrier needs a separate board part.
Board Part Files will be delivered with our Reference Designs on our https://shop.trenz-electronic.de/en/Download/?path=Trenz_Electronic/<module_name>/Reference_Design/<vivado_version>/<design_name>.
Board Part Files are locate in the subfolder <design_name>/board_files/ of the downloadable Reference Design. For more of the zip-file folder structure see: Project Delivery - Directory Structure.
This folder includes also a *_board_files.csv file with a list of all available board parts. This list is only used by TE-Scripts.
See Vivado Board Part Installation and Project Delivery - QuickStart