An article I found used this notaion for an IP address:
download a file named wget.sh from the IP address 136.144.41[.]169
what's the point of braces here and what's the difference between: 136.144.41[.]169 and 136.144.41.169?
[.] is not part of the IPv4 address standard. It is simply 0-255 four times separated by periods.
I'm guessing the site had a formatting error. Original link