Install devhelp by entering the following commands in the terminal:
sudo apt update sudo apt install devhelp
Description:
GNOME developers help program
Devhelp's primary goal is to be an API documentation browser for GNOME. It is able to scan for .devhelp files generated automatically for packages that use gtk-doc-tools to generate documentation for libraries and programs. . Devhelp provides some integration capabilities, which is used to allow command-line searches, emacs integration and embedding in applications like the Anjuta IDE.
Homepage: https://wiki.gnome.org/Apps/Devhelp
Version: 3.28.1-1
Section: devel