Standard user modes are listed in help/opers/umode
Standard server notice masks are listed in help/opers/snomask
Standard channel modes are listed in help/opers/cmode

The sgml docs have more detailed descriptions.

User mode +h (hide hostname) is provided by contrib/ip_cloaking.so
Server notice mask +F (far connects) is provided by contrib/sno_farconnect.so

# $Id: modes.txt 996 2006-03-09 01:14:34Z jilles $