"varname"[TAB]"varvalue"[NEWLINE]
Example:
"RealName" "??" "HomePage" "??" "Address" "??" "Telephone" "??" "MaxMBSize" "10000"
contains user default values for new users that are not set during the new account creation. This file is looked up in two different places, first in '$MAIL_ROOT/domains/DOMAIN' then in '$MAIL_ROOT', where 'DOMAIN' is the name of the domain where We're going to create the new user.
For each 'domain' handled by the server we'll create a directory 'domain' inside $MAIL_ROOT. Inside $MAIL_ROOT/'domain' reside 'domain'->'account' directories ($MAIL_ROOT/'domain'/'account'). This folder contains a sub folder named 'mailbox' (or 'Maildir/(tmp,new,cur)') that stores all 'account' messages. It also contains a file named 'USER.TAB' that stores``account'' variables, example:
"RealName" "Someone User" "HomePage" "http://www.some-server.org/someone.html" "MaxMBSize" "30000"