Z:gnu-www-ja-gpl-2.0-faq--94d312-Some templates make calls into/en

Some templates make calls into Javascript functions. Since Javascript is often non-trivial, it is worth copylefting. Because the templates will be combined with user data, it's possible that template+user data+Javascript would be considered one work under copyright law. A line needs to be drawn between the Javascript (copylefted), and the user code (usually under incompatible terms).