I do some editing for Wiki A, which is generally licensed in a typical wiki fashion:
Content is available under GNU FDL 1.3 unless otherwise noted.
Wiki B uses some templates I'd like to copy for reuse on Wiki A, and its general license is almost identical, except it's CC BY-SA 3.0 instead of FDL. I assume reuse of Wiki B's content on Wiki A is fine as long as the differing license is clearly stated.
The templates themselves include this wording in their documentation:
This is a chart based on [outside project] (GPLv3, CC BY-SA 3.0) which [author] at [Wiki B] authored.
My first reading of this is that the GPL/CC-BY-SA license refers specifically and exclusively to the outside project, and does not seem to state that the templates are licensed under these terms. This leads me to believe the templates are covered by Wiki B's general license. However, the author indicates to me that these wiki templates might be GPL licensed, which is an interpretation of the templates' wording I hadn't considered, but might be valid. The author also points out that it's the code that's GPL licensed, and data content that's CC-BY-SA. The outside project itself is published on Github, but does not appear to include these templates directly.
I'm waiting on clarification of the author's stance on the exact license the templates fall under, but I think this situation warrants good answers to these questions:
In the general case, are user-created wiki templates usually licensed the same as the wiki content, or are they treated differently due to "not being content"? Is posting attribution (author, origin, license) on the templates' documentation enough to satisfy Wiki B's license and the "unless otherwise noted" clause in Wiki A's license?
In this specific case, if the templates are indeed GPLv3 licensed, does that change the requirements in any way?