I was following [this](https://www.digitalocean.com/community/tutorials/how-to-set-up-nginx-with-http-2-support-on-ubuntu-16-04) guide from digital ocean and I saw the bracket colons. What does the listen [::]:443 ssl http2; block mean. The one before already specified it was listening on 443 so what does the[::]: do?
I think it means “all ipv6 addresses”. So it means listen on port 80 on all ip v6 addresses.