-.BR masquerade:
-.RS 5
-This directive controls two different types of email address masquerading.
-The two possible values, which may be specified in any combination on the
-line, separated by spaces, are \*(lqdraft_from\*(rq and
-\*(lqusername_extension\*(rq.
-.PP
-\*(lqusername_extension\*(rq, when specified on the \*(lqmasquerade:\*(rq line, allows a second
-type of username masquerading. If the user sets the
-.B $USERNAME_EXTENSION
-environment variable, its value will be appended to the actual login name. For
-instance, if I am \*(lqdan@company.com\*(rq, and I set
-.B $USERNAME_EXTENSION
-to \*(lq\-www\*(rq, my mail will appear to come from \*(lqdan\-www@company.com\*(rq. This is meant
-to interact with qmail's \*(lquser\-extension\*(rq feature, where mail sent to
-.IR user \- string
-will be delivered to
-.IR user .
-Likewise, those using
-versions of sendmail for which \*(lqplussed user\*(rq processing is active can set
-.B $USERNAME_EXTENSION
-to \*(lq+\fIstring\fR\*(rq. These MTA features are useful
-because they allow one to use different email addresses in different situations
-(to aid in automatic mail filtering or in determining where spammers got one's
-address) while only actually having a single account. Note that
-.B $USERNAME_EXTENSION
-is only appended to the username when \fIpost\fR is
-generating \*(lq[Resent\-]From:\*(rq lines and the SMTP envelope
-\*(lqFrom:\*(rq.
-.BR inc ,
-for instance, will not try to read from a maildrop file called \*(lqdan\-www\*(rq (to
-recall the earlier example).
-.PP
-\*(lqdraft_from\*(rq controls the most powerful type of address masquerading. Normally,
-when a user explicitly specifies a \*(lqFrom:\*(rq header in a draft,