I might be doubly misunderstanding this, because my first concern was that this could be used to impersonate government services; but; my second thought was (as someone with no idea of web tech stacks), perhaps this is a reimplementation using a different stack (Vue) of the original, for use for the same purposes?

Basically, you want to build a gov.uk site using your preferred stack, which happens to be the same as this, use this instead?

Again, many be completely misunderstanding, so hopefully someone can clarify.