The distribution contains generated data. If you want to contribute please hack your way directly via the source repository.
For developing, you will need to install uucd and download a copy of the XML Unicode character database to support/ucd.xml (this will be done automatically if the file doesn't exist). Type:
ocaml ./pkg/build_support.mlThe result are in files src/uucp_*_data.ml. They contain data extracted from the Unicode character database. These files are ignored by git.