I am using Kubuntu 20.04 with breeze-icon-theme as default.
$ dpkg --get-selections | grep icon-theme adwaita-icon-theme install breeze-icon-theme install gnome-icon-theme install hicolor-icon-theme install humanity-icon-theme install
$ LC_ALL=C aptitude show libgtk-3-0 Package: libgtk-3-0 Version: 3.24.17-3ubuntu1 State: installed Automatically installed: yes
I am using Kubuntu 20.04 with breeze-icon-theme as default.
$ dpkg --get-selections | grep icon-theme
adwaita-icon-theme install
breeze-icon-theme install
gnome-icon-theme install
hicolor-icon-theme install
humanity-icon-theme install
$ LC_ALL=C aptitude show libgtk-3-0
Package: libgtk-3-0
Version: 3.24.17-3ubuntu1
State: installed
Automatically installed: yes