Where is man:/ protocol handler configured?

[Karl Klinger]

Until recently, when I entered #command or man:/command at the alt-f2 
command prompt the man page for command would be displayed in konqueror. 
  Now when I try this, firefox opens with the message "Firefox doesn't 
know how to open this address, because the protocol (man) isn't 
associated with any program.".

If I enter settings:/ at the command prompt, the settings protocol opens 
in konqueror as expected.

Somehow I messed up the man:/ protocol handler setting.  Does anyone 
know how to fix it?

Karl