In Ubuntu 17.04 or newer, there is a script at /etc/update-motd.d/50-motd-news that reads https://motd.ubuntu.com/ and displays that text with the rest of the MOTD.

Currently, https://motd.ubuntu.com shows a news item about HBO's Silicon Valley which has a reference to Ubuntu.
Instead, https://motd.ubuntu.com should show relevant items to those that
use Ubuntu Server (relevant security issues, etc), instead of items for desktop users.

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Welcome to Ubuntu 17.04 ...