Said to be the source code for Guy Steele's RABBIT Scheme compiler.

Link found on the History of Lisp - Software Preservation Group page
here: http://www.softwarepreservation.org/projects/LISP/

Original URL:
http://www-2.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/scheme/impl/rabbit/rabbit.lsp

Also available here:
ftp://ftp.cs.indiana.edu/pub/scheme-repository/imp/RABBIT.gz

Disclaimer: I don't claim any ownership of this code, I'm simply
making it available for posterity, and for its instructional
value. The code was made available at the links given above without
any copyright notice. Use at your own risk.