it's rare to have trouble with our copyright being too restrictive.
My read is the GNU FDL prevents restrictions other than the ones that
the FDL applies, so "this document itself may not be modified in any
way, except as needed for the purpose of developing Internet standards"
may conflict with the GNU FDL's permission of unlimited derivative works.
However, my head spins when I try to actually resolve things like this
so I will leave it to the experts. (And 2026 doesn't have a copyright
statement on it, so its status per se is relatively unclear [to me].)
actually what the Wikipedia does is creating a derived work, not a modified
version... what's there doesn't claim to be 2026 or a revised version
thereof.