e.g. Where are the libpng's: ls -ld $(locate -r libpng.*\.so.*)
In the GUI app gnome-tweaks: Extensions > Desktop icons > Gear icon will give you 3 sizes -- small is still, too small, but you can modify what "small" is by editing the values listed in the variables ICON_SIZE, ICON_WIDTH and ICON_HEIGHT in
/usr/share/gnome-shell/extensions/desktop-icons@csoriano/prefs.js
(switching what happens when you press, F1/F2/F... and when you hold them down with Fcn):
Fn + Esc
If the super/win key does not work in Ubuntu Plasma:
Alt+F1
is sometimes Alt and other times Esc
Super/win + d