Here's what you'll find here:

XFree86-3.3.6/:  XFree86 3.3.6 from Slackware 7.1, with Mesa 3.2, and xpm-3.4k,
    linked against glibc-2.1.  It'll stay in here for a while (at least until
    we're reasonably sure that XFree86-4 is working well for all the hardware
    that this version works with).

libc4-attic/:  Packages providing old libc4 (otherwise known as "a.out")
    libraries.  These might be needed if you have to run very old Linux
    binaries.  Running "ldd" on binaries that require these libraries will
    show them to be linked with libc.so.4.

libc5-attic/:  Packages providing old libc5 (ELF, but pre-glibc) libraries.
    These might be needed if you have to run older Linux binaries linked
    with Linux libc5, an older derivative of GNU libc.  Running "ldd" on
    binaries that require these libraries will show them to be linked with
    libc.so.5.

wu-ftpd-2.6.1/:  The wu-ftpd FTP server.  This has traditionally been the
    default FTP server in Slackware (pretty much from the very beginning),
    but it has had its share of problems over the years, and with the
    emergence of better alternatives that are also free, wu-ftpd can no
    longer be considered our best choice for a default ftpd.  It's still
    an excellent FTP server, though, so it will remain here as an
    alternate choice.