The ftp file was produced by using the 'abc -p' option for packing a workspace. To unpack it in your own workspaces, you have to have ABC version 1.03 or higher. In this case, you should obtain the 'wrapped' version of the file, where long lines have been wrapped into lines of maximum length 80. This format is described in the header of the wrapped file. The program 'wrap.c' in this directory both wraps and unwraps such files.
Some directories also contain a file 'article' which describes the program in greater detail.
This workspace also contains how-tos for set, sequence, tree, and graph handling.