The 'nixpub' was a listing of UUCP hubs and Public Access UNIX Systems.
There was usually a short (one line) listing and then a longer listing.
Here are both (in long form) for a few of SDF's entries.

04/92  214-436-3281^      sdf        Dallas          TX 3/12/24/96  24
  i386-25, ISC SysVr3.2 UNIX; 4-way rotary at 436-3281, 2400bps except
  PEP on 436-5935.  Unrestricted free shell access, PinkBBS available.
  Operated and funded entirely by users.  500MB on-line storage.
  1000+ newsgroup full feed.  Internet mail.  On-line software includes
  emacs, trn, nn, elm, nethack, tinyMUD, etc.  Mail and news feeds
  available.
  Contact iczer@sdf.lonestar.org (Ted Uhlemann).

03/93 214-436-3281^    sdf        Dallas          TX 300-FAST  24
  i386-25, ISC 2.0.1; sdf public access Unix.  4-line rotary, 2400 bps,
  14.4k (436-4259), PEP (436-5935).  No fees but supported entirely by
  donations.  Shell accounts, UUCP mail and news feeds available.
  Providing access to Internet mail, 1600+ newsgroup full-feed UseNet,
  online games, RoundTable online chat, programming utilities, and more.
  Login as "new" for sample access and/or immediate account registration.
  Contact: admins@sdf.lonestar.org

03/94 214-248-9811      sdf        Dallas          TX 300-FAST  24
  i386/25 isc 2.0.1;  sdf.lonestar.org;  8-line rotary, 2400 bps, 14.4k, PEP;
  No Fees;  Shell account and UUCP mail/news feeds available;  Providing
  access to Internet E-Mail, 1600+ USENET newsgroups, online games, pro-
  gramming utilities and more.
  login 'info' for registration information.
  contact:  smj@sdf.lonestar.org