The -d0.1 (a.k.a. -d0) debugging switch previously prevented sendmail from forking and detaching itself, but that function has been moved to the -d99.100 debugging switch. The -d0.1 debugging switch now just tells sendmail to print information about its version:

Version 8.12.7
Compiled with:   LOG MATCHGECOS NAMED_BIND NDBM NEWDB NETINET NETUNIX
                 NIS
=  ==  ==  ==  ==  ==  = SYSTEM IDENTITY (after readcf) =  ==  ==  =
            (short domain name) $w = here
        (canonical domain name) $j = here.US.EDU
               (subdomain name) $m = US.EDU
                    (node name) $k = here
=  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  ==  =

The Version is the current version of sendmail. Note that for Sun the number can look like SMI-8.7.5 or 8.12.3+Sun.

The Compiled with: lists the compile-time definitions that were specified when sendmail was compiled. All the available definitions are listed in Table 3-2 in Section 3.2.

The SYSTEM IDENTITY shows the value assigned to four important macros. The meaning of each macro is shown in Table 21-7 in Section 21.9.