For my self learning, how do you see those requests?

Since you're asking explicitly, here's a hack-ish non-Libertine way to watch outgoing (DNS) connections. Note that deb packages use xz compression nowadays that is not supported by UT's tar. So extraction of the binary has to be done on a device with a more recent version of tar.

# Download armhf deb package of tcpdump.  There are newer package versions on the server, but those may not work as easily because of further dependencies.
$ wget http://ports.ubuntu.com/ubuntu-ports/pool/main/t/tcpdump/tcpdump_4.7.4-1ubuntu1_armhf.deb
# Extract deb archive.
$ ar -x tcpdump_4.7.4-1ubuntu1_armhf.deb
# Extract binary.
$ tar -xf data.tar.xz 

Now, move file usr/sbin/tcpdump to the UT device (via adb, ssh, cloud). Then switch to a terminal on the UT device.

# Make the binary executable.
$ chmod +x tcpdump
# Watch all DNS queries on the device.
$ sudo tcpdump -i any port 53

Then wait and see.

(Tested on OPO OTA-16 RC/W09).