Install doublecmd-help-en by entering the following commands in the terminal:
sudo apt update sudo apt install doublecmd-help-en
Description:
Documentation for Double Commander (English)
This package contains the documentation files for the Double Commander designed to be viewed in an external web browser. . This package contains the English documentation.
Homepage: http://doublecmd.sourceforge.net/
Version: 0.8.0-1
Section: universe/doc