Okay, I know the obvious answer is the history of the files. But how can I, from the command line, really understand what is hiding inside that .git directory?

Today I was doing one of my periodic disk space audits, trying to figure out where my usage goes. This comes from having a 64GB drive mounted as /home on my Linux laptop. I found some 15G of old video files to delete today, so I'm no longer as pressed for space. But my interest was piqued by one thing I have downloaded from Github that is ~120 megs for a very simple program. Poking around further I find that most of that usage is a single file:

$ ls -lh withExEditorHost/.git/objects/pack/pack-df07816cd15fb091439112029c28ebc366501652.pack
-r--r--r-- 1 elijah elijah 102M Mar 14 23:28 withExEditorHost/.git/objects/pack/pack-df07816cd15fb091439112029c28ebc366501652.pack
$ file withExEditorHost/.git/objects/pack/pack-df07816cd15fb091439112029c28ebc366501652.pack
withExEditorHost/.git/objects/pack/pack-df07816cd15fb091439112029c28ebc366501652.pack: Git pack, version 2, 299 objects
$

Is there a unzip or tar xzf equivalent for Git pack files? Naive usage of git unpack-file is only generating errors for me.