Well, I figured out this problem. 6.0.1 is based on Ubuntu Precise. Boxes was
built for Trusty. I have the Trusty kernel, but the rest of my packages are
still from the Precise release. I had found the Boxes package on Ubuntu
Updates, but if I want to install it, I have to update a LOT of dependencies,
one by one. I could probably do it, once I figure out the chain of
dependencies, but it would take some time.
I could update to Trisquel 7 and get it from the repos. But, I wanted to test
out 7 in a virtual machine first, so... that defeats the purpose.
Unless it's safe to add an Ubuntu PPA, download and install Boxes with
dependencies, and then remove the repository.
