Install gir1.2-appindicator-0.1 by entering the following commands in the terminal:
sudo apt update sudo apt install gir1.2-appindicator-0.1
Description:
Typelib files for libappindicator1.
. This package can be used by other packages using the GIRepository format to generate dynamic bindings.
Homepage: https://launchpad.net/libappindicator
Version: 12.10.1+18.04.20180322.1-0ubuntu1
Section: universe/introspection