Postfix help on command line

I just tried to get some information on the postfix website, but I can not access it. The website seems to be down. So I take this opportunity to write about how to get postfix help on the command line:

Show a list of all postfix man pages in the postfix section:
# apropos -s 8postfix ".*"

Show all man pages for a specific configuration entry. In this case we are searching for all man pages that provide information about configurations entries that contain the string "queue_lifetime":
# man -s 8postfix -wK queue_lifetime

Show a brief description of all possible postfix configuration settings:
# man 5 postconf

Show postfix templates:
# postconf -t