Add xplns to the list. It is free to distribute but the source is not
available.
I let this lay longer than I intended. We haven't completely decided
what is and what isn't acceptable for our ISO. Do we require all
packages to be Free/Open Source, do we require all packages to meet
Debian standards for inclusion, do we accept packages that are freely
distributable even if source isn't available, etc.? I realize that it
we go with a laxer standard for inclusion we won't be in lockstep with
DebianEdu, but I'd hate to see good, useful educational software that we
have permission to distribute be avoided for philosophical reasons
without our having examined our reasoning closely enough.