Licensing XLS-Forms

Hi there,

we have been tasked with developing a toolbox for measuring walkability to be used by German municipalities. It will definitely be based on XLS-Form and the forms will be publicly available afterwards (supposedky via GitHub). Therefore I'm now asking myself what kind of licensing model could be suitable for XLS-Forms. Are XLS-Forms seen as a software snippet, so that GPL or Apache could be an option or rather some kind of structured text, so maybe Creative Commons could be applied?

Any thoughts or experiences on that?

Thanks in advance