The index uses the Glimpse (glimpse(1)) text indexing system. Many of the glimpse options, regular expressions, and wildcards are valid: see the help page for a summary.
Glimpse was developed by Udi Manber and Burra Gopal of the University of Arizona, and Sun Wu of the National Chung-Cheng University, Taiwan. You may contact the authors at glimpse@cs.arizona.edu
The Manual Page text search interface was created for Linux by Michael Hamilton.