When I read this;
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
it sounds like I can't put a nice title page on the document and that I can't vary anything in the original.
Yes, I know what that it is supposed to mean but unfortunately English is my first language.
I read "no invariant sections" as meaning that you can add sections to the original text but you can't mark them as unmodifiable by others. But I have no idea what the other stuff means.
Ah, It's your tag. "don't dazzle me with jargon"
I always thought it should just say it;
Permission is granted to copy... however no sections can be marked as unchangable and no text can be required to be included before or after this document.