Squeak is an allegedly "open source" project that I saw mentioned on
lwn.net; looking at the license (http://squeak.cs.uiuc.edu/license.html)
A quick glance makes it look non-free, though: it doesn't permit
modification/derivation of the *fonts* included -- though I'd guess
those could be put in non-free, and the rest in contrib, except that
there's also an Indemnification clause and an Export Law clause. It
looks like the DFSG doesn't really say anything about Indemnification,
but the Export Law clause is a restriction on redistribution... it
happens to *evaluate* to "obey the law", but as we've argued here in
the past, that doesn't belong in the *license*.