Install gir1.2-mypaint-1.3 by entering the following commands in the terminal:
sudo apt update sudo apt install gir1.2-mypaint-1.3
Description:
GObject introspection data for libmypaint
This package contains GObject introspection information. . It can be used by packages using the GIRepository format to generate dynamic bindings.
Homepage: https://github.com/Jehan/mypaint-brushes
Version: 1.3.0-2
Section: universe/introspection