It's annoying but it can be dealt with. The distinction I, personally,
was trying to make is that that's a finite, known, limited amount. You
didn't respond to the point that the amount for the GFDL is not a
maximum amount at all, just a current amount.
I see the distinction, but I don't think it makes a significant
difference, since in any real case it is a given amount.
The GFDL allows arbitrarily large amounts of invariant text. Do you
agree that, say, 1000 pages of invariant text would be non-free?
I am not sure. I would consider 1000 pages unacceptable in practice,
unless the manual itself is much bigger. That much makes publication
of a modified manual as a manual unfeasible. But I hesitate to say
that it would be non-free. Would a 1000-page license be automatically
non-free? I'd probably refuse to use software with such a long
license, since I would not want to read the whole license, and I would
not bother checking whether it had any non-free requirements. But I
hesitate to say it would be non-free just because of its length.
I would not release a reference card under either the GFDL or the GPL,
because both of them are long enough that the requirement to
distribute them along with the reference card is burdensome.
But surely this doesn't imply they are non-free licenses.
With the GFDL'ed reference card, since the "Invariant Section" text is
the majority of the text, I'd be doubtful that it could qualify as
"Secondary" at all: it may be the main topic by sheer volume. So it may
not even be distributable.
The invariant sections don't define the main topic, because
interpreting them as the main topic is inconsistent with the GFDL's
requirement that they be secondary.
Further "Invariant Section" problem: I can't use parts of the GCC manual
in an essay on the funding of free software
For the manual to be free, you must be able to publish a modified
version of the manual. In other words, a modified manual.
Being able to use some of the text for something of a different kind,
such as an essay about the funding of free software, is something above
and beyond the call of duty for a license.
