Install sylpheed-doc by entering the following commands in the terminal:
sudo apt update sudo apt install sylpheed-doc
Description:
Light weight e-mail client with GTK+ (documentation)
This package holds the documentation for sylpheed mailer. It is an HTML manual which describes all the features of sylpheed. . All translations are included in this package.
Homepage: http://sylpheeddoc.sourceforge.net/
Version: 20140827-1
Section: universe/doc