Comment 7 for bug 1958224

As mentioned by Sebastien above, I have a smiliar issue which is blocking the use of the USB as serial port for use with Arduino. If this helps, my dist-upgrade log is available in another bug report if you want to have a look: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1969353

Based on the content, it looks to me like brltty was already there prior to upgrade and I also woudn't have used brltty during installation which was only done 2-3 weeks before upgrade.

I also just did a fresh install in a virtual machine and brltty is also there. It looks to me like this package is a dependancy of ubuntu-desktop or similar through orca:
$ apt-cache rdepends brltty
brltty
Reverse Depends:
  brltty-espeak
  xubuntu-desktop
  vanilla-gnome-desktop
  ubuntukylin-desktop
  ubuntu-unity-desktop
  ubuntu-budgie-desktop
  speechd-el
  brltty-x11
  brltty-speechd
  brltty-flite
  orca
  ubuntu-desktop-minimal
  ubuntu-desktop

for info, I did also check on a fresh Debian Testing install and the package isn't installed by default there.