gman binary package in Ubuntu Focal amd64

 Gman is a simple front-end for the manual page system. The most basic job
 of gman is to build a database for all the man pages and display them
 (or part of them) on the screen. When user decides to read a man page,
 gman will launch an external viewer to display the manual page. More than
 one external viewer windows can be launched at the same time.
 .
 The default manual page viewer is a terminal window with the original
 man(1). It can also launch gv, evince, or a link to a CGI script which
 utilizes man2html, for viewing manual pages using a web browser.
 .
 There is an index search function to look for the man pages that one needs.
 It's simple, but it's useful.

Source package