Install libicns1 by entering the following commands in the terminal:
sudo apt update sudo apt install libicns1
Description:
library for manipulation of the Mac OS icns format
libicns is a library for manipulation of the Mac OS icns resource format, also known as the IconFamily resource type. It can read and write files for the Mac OS X icns format, as well as read from Mac OS resource files and macbinary encoded Mac OS resource forks.
Homepage: http://icns.sourceforge.net/
Version: 0.8.1-3.1
Section: universe/libs