libgtkextra-3.0 binary package in Ubuntu Lunar amd64

 The library includes the following widgets:
 .
 GtkSheet, a matrix widget; GtkPlot, which allows you to draw high quality
 scientific plots; the package also includes GtkPlot3D and GtkPlotPolar;
 GtkPlotCanvas is a GtkFixed subclass and allows you to DnD plots etc.
 The distribution includes also a PostScript driver.
 GtkIconList, which allows you to display a table of xpm icons;
 GtkDirTree, which allows you to navigate the file-system; GtkFileList
 which displays the contents of a given directory using fancy icons
 for different types of files; GtkIconFileSelection, a file selection
 dialog using icons; GtkItemEntry, a GtkEntry subclass; GtkFontCombo,
 providing two combos to select among the 35 standard Adobe PostScript
 fonts; GtkComboBox, which allows you can pack whatever you want, from
 a calendar to a clist; GtkColorCombo, to pickup the color you like
 the most, within a palette; GtkBorderCombo, a fancy GtkComboBox subclass;
 GtkCheckItem, a GtkCheckButton hack with the look and feel of
 the Redmond95 theme.

Source package