What is the meaning of read -r ?

in order to understand another answer:

find / -type d -print0 | while read -r -d ''; do ls -ltr "$dir" | sed '$!d'

the first step is to understand the usage of the option -r of the read command.

First, I thought, it would be sufficient to simply execute

man read

to lookup the meaning of the -r option , but I realized the man page does not contain any explanation for option at all, so I googled for it got some read -t , read -p examples but no read -r .