Okay, so that part is not clear, but it is there...
How long has "GNU Free Documentation License, Version 1.2 or any later
version published by the Free Software Foundation; with no Invariant
Sections, with no Front-Cover Texts, and with no Back-Cover Texts."
been at the bottom of the edit page? Just wondering.
Years. I don't know about since the beginning, but certainly a long time.
And in these cases, why hasn't wikipedia been
completely compatible
with CC-BY-SA since its beginning? I was under the impression the only
sticking point were these parts.
I believe the GFDL requires derived works to be distributed under the
GFDL, not just a license that is similar to the GFDL, so isn't
compatible with any other license however similar it may be. (IANAL,
YMMV, OMGWTFBBQ)
The statement at the bottom of the page should
indicate the invariant
exception btw, it is unclear that you are pointing to a document that
needs further clarification, even with the link to
Wikipedia:Copyrights, which btw implies that there might be cases
where Invariant Sections could be included under the non-invariant
GFDL version that wikipedia uses.
Linking to the verbatim text of an incomplete license isn't desirable ;)
It does indicate it - you just have to follow the footnote.