in 2009 I bought a new 13-inch MacBook Pro which was sold to the Mac User group to use with the book lending library. I mostly used it while connected to power so didn't care about the battery-sapping aspects of running a 7200 rpm drive in it, it was much faster than with the 5400 rpm unit it shipped with.
I was using it yesterday at the MUG's monthly meeting and when packing it away observed that for some reason its power supply had grown enormously. No way was it that big when I owned it. I recall it being a square configuration 60 watt unit.
But the one that was in use with it was a rectangular unit, a standard Apple device, not a 3rd-party one. The Magsafe cable sprouted from the long side of the rectangle. Checking online revealed it to be an 85 watt unit from a 15 or 17-inch MacBook Pro.
Dunno why it's using such a thing, but I guess it shows that Apple's chargers are smart ones & won't deliver more current than the machine can handle.