I salvaged this capacitor off a circuit board but don't know how to categorise it. I expected to see a voltage and a capacity.

Edit: also, what the deal with this capacitor's third leglette?

 

The third leg is used as an anchor as the cap is quite large.
Sometimes it is not connected to anything but soldered on to the PCB and sometimes it may be connected to GND or negative terminal of the cap

 

Surface mount components often use shorthand notation. You need to use the manufacturer datasheets to decipher.

As already mentioned, large capacitors often have leads/terminals that are used for mechanical support:


In this example, the support terminals can't be electrically connected.

 

Thanks!

For Panasonic, the voltage code is E = 25 V and the 68 is uF. http://www.mouser.com/ds/2/315/ABA0000C1181-947564.pdf