I'm closing this based on the most recent comment. adwaita-icon-theme Suggests adwaita-icon-theme-legacy which means it's not installed by default but it's mentioned in apt's output when using apt from the command line.
** Changed in: adwaita-icon-theme (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2073533 Title: Some icons are missing from GNOME's default icon theme To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/adwaita-icon-theme/+bug/2073533/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs