Relevant text from FSF's "Covenant Not to Assert"
as published circa late 2006-07 (around time of GPLv3 Second Discussion Draft)

I (Bradley M. Kuhn) carefully went through FSF's "Covenant Not to Assert",
which appears to have been published on Wednesday 2 August 2006 (a few days
after the second GPLv2 discussion draft published on Thursday 27 July 2006),
and merged in any relevant text and descriptions that might be of use in this
tutorial.

However, since the patent provisions changed some much over the drafting of
GPLv3, there was not much text useful to bring in on this one.

The raw material used for this commit can be found here:
http://gplv3.fsf.org/opinions-draft-2.html
Specifically, a copy of the LaTeX sources are here:
http://gplv3.fsf.org/covenant-not-to-assert-dd2.tex

As I merged in this text, I added FIXME's where it seemed the text was
incomplete or referred to parts of GPLv3 draft text that disappeared in later
versions.

Finally, note that this material was originally copyrighted and licensed as
follows:

Copyright © 2006 Free Software Foundation, Inc.

Verbatim copying and distribution of this entire article are permitted
worldwide, without royalty, in any medium, provided this notice, and the
copyright notice, are preserved.

However, I am hereby relicensing this material to CC-By-SA-4.0, with the
verbal permission from John Sullivan, Executive Director of the FSF, which
was given to me during a conference call on Wednesday 12 February 2014.