For the terminally curious, the term “Aegis' own transfer format” means an optionally BASE64 encoded, optionally gzipped, CPIO archive. The top-level directory indicates whether the archive file is a source file, meta-data, etc.
All the files in the tarball have the project name and version added as a default path prefix, so they unpack into a single directory. If you don't want the extra top-level directory, use these links: tar.gz (entire source).
The version of aedist used by this server is 4.25.C681. To work out what version of aedist you have at your end, use the “aedist --version” command.
A downloaded change set usually contains only the files in the changset itself. The entire source options, above, include the rest of the project source files in the downloaded change set.