With our policy to ship all parameters in our configuration files, it's hard to get an overview over any configuration you've changed from the defaults.
The proposed function is present in both postconf (from Postfix) and doveconf (from Dovecot) and it's a really handy to have in a command line tool that handles configuration.
> [root@juno ~]# postconf -n
> alias_database = hash:/etc/aliases
> alias_maps = hash:/etc/aliases
> command_directory = /usr/sbin
> config_directory = /etc/postfix
> content_filter = amavis:[127.0.0.1]:10024
> daemon_directory = /usr/libexec/postfix