I want to install sensors-applet onto my Ubuntu 12.04 computer. The instructions on this (and other) webpages says to enter this command in a command terminal:

sudo apt-get install sensors-applet

This is a gnome applet and gnome isn't exactly obscure. Why can sensors-applet package not be found?

Before you say "no", note that I was able to execute "gnome-panel" to add a bar/panel along the bottom of my desktop, add 8 cpu-frequency applets to the bar (one per CPU core), and add gnome-panel to my startup applications. So I've already done the basics, and believe all I need now is to be able to download and install the sensors-applet to have that temperature applet available on the panel too. See here.