gtklp binary package in Ubuntu Focal amd64

 GtkLP lets you print files under the Common Unix Printing System
 (CUPS). Written in GTK+ 2.0 and for the GNOME desktop environment,
 it supports multiple option settings for each printer it knows,
 with all the standard CUPS options available.
 .
 Other features include localized dialogs for several languages, as
 well as multiple interfaces; with a little more effort, you can use
 GtkLP as a drop-in replacement for `lp'.

Source package