[Dovecot] dovecot -n output of (default) is confusing me

Hello,

I'm new to dovecot and I've been taking my time examining what makes dovecot work. If I have imap and pop3 listed as protocols, dovecot -n outputs:

mail_executable(default): /usr/local/libexec/dovecot/imap mail_executable(imap): /usr/local/libexec/dovecot/imap mail_executable(pop3): /usr/local/libexec/dovecot/pop3

I don't understand why imap is listed twice once as (default), and the other without (default). As a secondary question, why would you want a default of imap as opposed to pop3?

Thanks.

John