Install libgtksourceview-3.0-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libgtksourceview-3.0-doc
Description:
documentation for the GTK+ syntax highlighting widget
GtkSourceView is a text widget that extends the standard GTK+ 3.x text widget GtkTextView. It improves GtkTextView by implementing syntax highlighting and other features typical of a source editor. . This package contains the GtkSourceView reference manual.
Homepage: https://wiki.gnome.org/Projects/GtkSourceView
Version: 3.24.7-1
Section: doc