This stub page replaces the home page for ACL2 Version 5.0. The original website for that version of ACL2 is stored as a collection of gzipped files, here:

http://www.cs.utexas.edu/users/moore/acl2/older-releases/v5-0/

In particular, the distrib/ directory contains the ACL2 source tarball, at acl2.tar.gz .