I noticed that several Wikipedias have a lua module (originally on test2) that provides some convenience functionality for handling Wikibase time values.

e.g. https://hu.wikipedia.org/wiki/Modul:Time and https://cs.wikipedia.org/wiki/Modul:Time

if we are to have this (seems useful), then I think it might be even more useful and maintainable if Wikibase could provide the module instead of copying it around on wiki.