Binary package “gmanedit” in ubuntu bionic

GTK+ man pages editor

 Gtk+ Manpages Editor is an editor for man pages that runs on X with GTK+.
 .
 Gmanedit is an application which allows you to edit manual pages (man) on
 Linux/Unix systems.
 .
 It is like most common HTML editors but more easy. You need to know manpages
 format.