Install charmap.app-common by entering the following commands in the terminal:
sudo apt update sudo apt install charmap.app-common
Description:
Character map for GNUstep (arch-independent files)
Charmap is a character map for GNUstep. It offers font selection, allowing one to easily see all the glyphs which a particular font provides. . This package contains the architecture-independent files.
Homepage: http://www.nongnu.org/charmap/
Version: 0.3~rc1-3build2
Section: universe/gnustep