What actually happens to the .box file (which according to the docs is simply a vbox image in tar form, in a particular format) after the first command

vagrant box add lucid32 http://files.vagrantup.com/lucid32.box

is executed?

I can't seem to find the filesystem location of lucid32.box after the download has successfully completed...

I am aware it doesn't really matter as

vagrant init lucid32
vagrant up
vagrant ssh

will get me into the vm irregardless.

But I am curious where .box is located.