helpman binary package in Ubuntu Bionic amd64

 Helpman provides a classified access to the manuals, installed by user/system
 programs, automatically. It also supports typing a program / manual name, in
 the Select Manual: text / combo box directly, to display it quickly. Error
 Messages will be shown below, if a manual is not found.
 .
 The Manual Type list box, shows sections 1 to 8, useful for specific display
 of a version of the manual. Say for example, if you see, CRON(8) in a manual,
 it means the CRON manual in the 8th section. So users should choose
 appropriately.
 .
 Please click the info button for more details.

Source package