Another piece of phone home software on #Ubuntu Linux: Have a look at /etc/update-motd.d/50-motd-news

# Piece together the user agent
USER_AGENT="curl/$curl_ver $lsb $platform $cpu $uptime"

At least no unique identifier, but why do they transmit the platform, CPU and uptime?

They are honest about ubuntu-report and popcon and allow you to disable it in the installer, but this file is installed by default without asking the user.