This wiki was in read-only mode for many years, but can now be edited again. A lot of information will need to be updated.
Config File
BZFlag uses an ASCII configuration file to store user settings. The file is called "config.cfg" and its location is dependant on your operating system.
Windows
XP: C:\Documents and Settings\[user]\My Documents\My BZFlag Files\2.0\config.cfg 
Vista: C:\Users\[user]\Documents\My BZFlag Files\2.0\config.cfg
(Of course, replace [user] with your username)
Mac OS X
~/Library/Application Support/BZFlag/2.0/config.cfg
Linux and unix platforms
~/.bzf/2.0/config.cfg